obtained gcc-4.6.4.tar.bz2 from upstream website;upstream

verified gcc-4.6.4.tar.bz2.sig; imported gcc-4.6.4 source tree from verified upstream tarball. downloading a git-generated archive based on the 'upstream' tag should provide you with a source tree that is binary identical to the one extracted from the above tarball. if you have obtained the source via the command 'git clone', however, do note that line-endings of files in your working directory might differ from line-endings of the respective files in the upstream repository.
author: upstream source tree <ports@midipix.org> 2015-03-15 20:14:05 -0400
committer: upstream source tree <ports@midipix.org> 2015-03-15 20:14:05 -0400
commit: 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree: 976dc5ab7fddf506dadce60ae936f43f58787092 /libgo/go/debug
download: cbb-gcc-4.6.4-554fd8c5195424bdbcabf5de30fdc183aba391bd.tar.bz2
cbb-gcc-4.6.4-554fd8c5195424bdbcabf5de30fdc183aba391bd.tar.xz
54 files changed, 8741 insertions, 0 deletions
diff --git a/libgo/go/debug/dwarf/buf.go b/libgo/go/debug/dwarf/buf.go
new file mode 100644
index 000000000..2d29cebdd
--- /dev/null
+++ b/libgo/go/debug/dwarf/buf.go
@@ -0,0 +1,154 @@
+// 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.
+
+// Buffered reading and decoding of DWARF data streams.
+
+package dwarf
+
+import (
+	"encoding/binary"
+	"os"
+	"strconv"
+)
+
+// Data buffer being decoded.
+type buf struct {
+	dwarf    *Data
+	order    binary.ByteOrder
+	name     string
+	off      Offset
+	data     []byte
+	addrsize int
+	err      os.Error
+}
+
+func makeBuf(d *Data, name string, off Offset, data []byte, addrsize int) buf {
+	return buf{d, d.order, name, off, data, addrsize, nil}
+}
+
+func (b *buf) uint8() uint8 {
+	if len(b.data) < 1 {
+		b.error("underflow")
+		return 0
+	}
+	val := b.data[0]
+	b.data = b.data[1:]
+	b.off++
+	return val
+}
+
+func (b *buf) bytes(n int) []byte {
+	if len(b.data) < n {
+		b.error("underflow")
+		return nil
+	}
+	data := b.data[0:n]
+	b.data = b.data[n:]
+	b.off += Offset(n)
+	return data
+}
+
+func (b *buf) skip(n int) { b.bytes(n) }
+
+func (b *buf) string() string {
+	for i := 0; i < len(b.data); i++ {
+		if b.data[i] == 0 {
+			s := string(b.data[0:i])
+			b.data = b.data[i+1:]
+			b.off += Offset(i + 1)
+			return s
+		}
+	}
+	b.error("underflow")
+	return ""
+}
+
+func (b *buf) uint16() uint16 {
+	a := b.bytes(2)
+	if a == nil {
+		return 0
+	}
+	return b.order.Uint16(a)
+}
+
+func (b *buf) uint32() uint32 {
+	a := b.bytes(4)
+	if a == nil {
+		return 0
+	}
+	return b.order.Uint32(a)
+}
+
+func (b *buf) uint64() uint64 {
+	a := b.bytes(8)
+	if a == nil {
+		return 0
+	}
+	return b.order.Uint64(a)
+}
+
+// Read a varint, which is 7 bits per byte, little endian.
+// the 0x80 bit means read another byte.
+func (b *buf) varint() (c uint64, bits uint) {
+	for i := 0; i < len(b.data); i++ {
+		byte := b.data[i]
+		c |= uint64(byte&0x7F) << bits
+		bits += 7
+		if byte&0x80 == 0 {
+			b.off += Offset(i + 1)
+			b.data = b.data[i+1:]
+			return c, bits
+		}
+	}
+	return 0, 0
+}
+
+// Unsigned int is just a varint.
+func (b *buf) uint() uint64 {
+	x, _ := b.varint()
+	return x
+}
+
+// Signed int is a sign-extended varint.
+func (b *buf) int() int64 {
+	ux, bits := b.varint()
+	x := int64(ux)
+	if x&(1<<(bits-1)) != 0 {
+		x |= -1 << bits
+	}
+	return x
+}
+
+// Address-sized uint.
+func (b *buf) addr() uint64 {
+	switch b.addrsize {
+	case 1:
+		return uint64(b.uint8())
+	case 2:
+		return uint64(b.uint16())
+	case 4:
+		return uint64(b.uint32())
+	case 8:
+		return uint64(b.uint64())
+	}
+	b.error("unknown address size")
+	return 0
+}
+
+func (b *buf) error(s string) {
+	if b.err == nil {
+		b.data = nil
+		b.err = DecodeError{b.name, b.off, s}
+	}
+}
+
+type DecodeError struct {
+	Name   string
+	Offset Offset
+	Error  string
+}
+
+func (e DecodeError) String() string {
+	return "decoding dwarf section " + e.Name + " at offset 0x" + strconv.Itob64(int64(e.Offset), 16) + ": " + e.Error
+}
diff --git a/libgo/go/debug/dwarf/const.go b/libgo/go/debug/dwarf/const.go
new file mode 100644
index 000000000..1a3fec155
--- /dev/null
+++ b/libgo/go/debug/dwarf/const.go
@@ -0,0 +1,433 @@
+// 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.
+
+// Constants
+
+package dwarf
+
+import "strconv"
+
+// An Attr identifies the attribute type in a DWARF Entry's Field.
+type Attr uint32
+
+const (
+	AttrSibling        Attr = 0x01
+	AttrLocation       Attr = 0x02
+	AttrName           Attr = 0x03
+	AttrOrdering       Attr = 0x09
+	AttrByteSize       Attr = 0x0B
+	AttrBitOffset      Attr = 0x0C
+	AttrBitSize        Attr = 0x0D
+	AttrStmtList       Attr = 0x10
+	AttrLowpc          Attr = 0x11
+	AttrHighpc         Attr = 0x12
+	AttrLanguage       Attr = 0x13
+	AttrDiscr          Attr = 0x15
+	AttrDiscrValue     Attr = 0x16
+	AttrVisibility     Attr = 0x17
+	AttrImport         Attr = 0x18
+	AttrStringLength   Attr = 0x19
+	AttrCommonRef      Attr = 0x1A
+	AttrCompDir        Attr = 0x1B
+	AttrConstValue     Attr = 0x1C
+	AttrContainingType Attr = 0x1D
+	AttrDefaultValue   Attr = 0x1E
+	AttrInline         Attr = 0x20
+	AttrIsOptional     Attr = 0x21
+	AttrLowerBound     Attr = 0x22
+	AttrProducer       Attr = 0x25
+	AttrPrototyped     Attr = 0x27
+	AttrReturnAddr     Attr = 0x2A
+	AttrStartScope     Attr = 0x2C
+	AttrStrideSize     Attr = 0x2E
+	AttrUpperBound     Attr = 0x2F
+	AttrAbstractOrigin Attr = 0x31
+	AttrAccessibility  Attr = 0x32
+	AttrAddrClass      Attr = 0x33
+	AttrArtificial     Attr = 0x34
+	AttrBaseTypes      Attr = 0x35
+	AttrCalling        Attr = 0x36
+	AttrCount          Attr = 0x37
+	AttrDataMemberLoc  Attr = 0x38
+	AttrDeclColumn     Attr = 0x39
+	AttrDeclFile       Attr = 0x3A
+	AttrDeclLine       Attr = 0x3B
+	AttrDeclaration    Attr = 0x3C
+	AttrDiscrList      Attr = 0x3D
+	AttrEncoding       Attr = 0x3E
+	AttrExternal       Attr = 0x3F
+	AttrFrameBase      Attr = 0x40
+	AttrFriend         Attr = 0x41
+	AttrIdentifierCase Attr = 0x42
+	AttrMacroInfo      Attr = 0x43
+	AttrNamelistItem   Attr = 0x44
+	AttrPriority       Attr = 0x45
+	AttrSegment        Attr = 0x46
+	AttrSpecification  Attr = 0x47
+	AttrStaticLink     Attr = 0x48
+	AttrType           Attr = 0x49
+	AttrUseLocation    Attr = 0x4A
+	AttrVarParam       Attr = 0x4B
+	AttrVirtuality     Attr = 0x4C
+	AttrVtableElemLoc  Attr = 0x4D
+	AttrAllocated      Attr = 0x4E
+	AttrAssociated     Attr = 0x4F
+	AttrDataLocation   Attr = 0x50
+	AttrStride         Attr = 0x51
+	AttrEntrypc        Attr = 0x52
+	AttrUseUTF8        Attr = 0x53
+	AttrExtension      Attr = 0x54
+	AttrRanges         Attr = 0x55
+	AttrTrampoline     Attr = 0x56
+	AttrCallColumn     Attr = 0x57
+	AttrCallFile       Attr = 0x58
+	AttrCallLine       Attr = 0x59
+	AttrDescription    Attr = 0x5A
+)
+
+var attrNames = [...]string{
+	AttrSibling:        "Sibling",
+	AttrLocation:       "Location",
+	AttrName:           "Name",
+	AttrOrdering:       "Ordering",
+	AttrByteSize:       "ByteSize",
+	AttrBitOffset:      "BitOffset",
+	AttrBitSize:        "BitSize",
+	AttrStmtList:       "StmtList",
+	AttrLowpc:          "Lowpc",
+	AttrHighpc:         "Highpc",
+	AttrLanguage:       "Language",
+	AttrDiscr:          "Discr",
+	AttrDiscrValue:     "DiscrValue",
+	AttrVisibility:     "Visibility",
+	AttrImport:         "Import",
+	AttrStringLength:   "StringLength",
+	AttrCommonRef:      "CommonRef",
+	AttrCompDir:        "CompDir",
+	AttrConstValue:     "ConstValue",
+	AttrContainingType: "ContainingType",
+	AttrDefaultValue:   "DefaultValue",
+	AttrInline:         "Inline",
+	AttrIsOptional:     "IsOptional",
+	AttrLowerBound:     "LowerBound",
+	AttrProducer:       "Producer",
+	AttrPrototyped:     "Prototyped",
+	AttrReturnAddr:     "ReturnAddr",
+	AttrStartScope:     "StartScope",
+	AttrStrideSize:     "StrideSize",
+	AttrUpperBound:     "UpperBound",
+	AttrAbstractOrigin: "AbstractOrigin",
+	AttrAccessibility:  "Accessibility",
+	AttrAddrClass:      "AddrClass",
+	AttrArtificial:     "Artificial",
+	AttrBaseTypes:      "BaseTypes",
+	AttrCalling:        "Calling",
+	AttrCount:          "Count",
+	AttrDataMemberLoc:  "DataMemberLoc",
+	AttrDeclColumn:     "DeclColumn",
+	AttrDeclFile:       "DeclFile",
+	AttrDeclLine:       "DeclLine",
+	AttrDeclaration:    "Declaration",
+	AttrDiscrList:      "DiscrList",
+	AttrEncoding:       "Encoding",
+	AttrExternal:       "External",
+	AttrFrameBase:      "FrameBase",
+	AttrFriend:         "Friend",
+	AttrIdentifierCase: "IdentifierCase",
+	AttrMacroInfo:      "MacroInfo",
+	AttrNamelistItem:   "NamelistItem",
+	AttrPriority:       "Priority",
+	AttrSegment:        "Segment",
+	AttrSpecification:  "Specification",
+	AttrStaticLink:     "StaticLink",
+	AttrType:           "Type",
+	AttrUseLocation:    "UseLocation",
+	AttrVarParam:       "VarParam",
+	AttrVirtuality:     "Virtuality",
+	AttrVtableElemLoc:  "VtableElemLoc",
+	AttrAllocated:      "Allocated",
+	AttrAssociated:     "Associated",
+	AttrDataLocation:   "DataLocation",
+	AttrStride:         "Stride",
+	AttrEntrypc:        "Entrypc",
+	AttrUseUTF8:        "UseUTF8",
+	AttrExtension:      "Extension",
+	AttrRanges:         "Ranges",
+	AttrTrampoline:     "Trampoline",
+	AttrCallColumn:     "CallColumn",
+	AttrCallFile:       "CallFile",
+	AttrCallLine:       "CallLine",
+	AttrDescription:    "Description",
+}
+
+func (a Attr) String() string {
+	if int(a) < len(attrNames) {
+		s := attrNames[a]
+		if s != "" {
+			return s
+		}
+	}
+	return strconv.Itoa(int(a))
+}
+
+func (a Attr) GoString() string {
+	if int(a) < len(attrNames) {
+		s := attrNames[a]
+		if s != "" {
+			return "dwarf.Attr" + s
+		}
+	}
+	return "dwarf.Attr(" + strconv.Itoa64(int64(a)) + ")"
+}
+
+// A format is a DWARF data encoding format.
+type format uint32
+
+const (
+	// value formats
+	formAddr        format = 0x01
+	formDwarfBlock2 format = 0x03
+	formDwarfBlock4 format = 0x04
+	formData2       format = 0x05
+	formData4       format = 0x06
+	formData8       format = 0x07
+	formString      format = 0x08
+	formDwarfBlock  format = 0x09
+	formDwarfBlock1 format = 0x0A
+	formData1       format = 0x0B
+	formFlag        format = 0x0C
+	formSdata       format = 0x0D
+	formStrp        format = 0x0E
+	formUdata       format = 0x0F
+	formRefAddr     format = 0x10
+	formRef1        format = 0x11
+	formRef2        format = 0x12
+	formRef4        format = 0x13
+	formRef8        format = 0x14
+	formRefUdata    format = 0x15
+	formIndirect    format = 0x16
+)
+
+// A Tag is the classification (the type) of an Entry.
+type Tag uint32
+
+const (
+	TagArrayType              Tag = 0x01
+	TagClassType              Tag = 0x02
+	TagEntryPoint             Tag = 0x03
+	TagEnumerationType        Tag = 0x04
+	TagFormalParameter        Tag = 0x05
+	TagImportedDeclaration    Tag = 0x08
+	TagLabel                  Tag = 0x0A
+	TagLexDwarfBlock          Tag = 0x0B
+	TagMember                 Tag = 0x0D
+	TagPointerType            Tag = 0x0F
+	TagReferenceType          Tag = 0x10
+	TagCompileUnit            Tag = 0x11
+	TagStringType             Tag = 0x12
+	TagStructType             Tag = 0x13
+	TagSubroutineType         Tag = 0x15
+	TagTypedef                Tag = 0x16
+	TagUnionType              Tag = 0x17
+	TagUnspecifiedParameters  Tag = 0x18
+	TagVariant                Tag = 0x19
+	TagCommonDwarfBlock       Tag = 0x1A
+	TagCommonInclusion        Tag = 0x1B
+	TagInheritance            Tag = 0x1C
+	TagInlinedSubroutine      Tag = 0x1D
+	TagModule                 Tag = 0x1E
+	TagPtrToMemberType        Tag = 0x1F
+	TagSetType                Tag = 0x20
+	TagSubrangeType           Tag = 0x21
+	TagWithStmt               Tag = 0x22
+	TagAccessDeclaration      Tag = 0x23
+	TagBaseType               Tag = 0x24
+	TagCatchDwarfBlock        Tag = 0x25
+	TagConstType              Tag = 0x26
+	TagConstant               Tag = 0x27
+	TagEnumerator             Tag = 0x28
+	TagFileType               Tag = 0x29
+	TagFriend                 Tag = 0x2A
+	TagNamelist               Tag = 0x2B
+	TagNamelistItem           Tag = 0x2C
+	TagPackedType             Tag = 0x2D
+	TagSubprogram             Tag = 0x2E
+	TagTemplateTypeParameter  Tag = 0x2F
+	TagTemplateValueParameter Tag = 0x30
+	TagThrownType             Tag = 0x31
+	TagTryDwarfBlock          Tag = 0x32
+	TagVariantPart            Tag = 0x33
+	TagVariable               Tag = 0x34
+	TagVolatileType           Tag = 0x35
+	TagDwarfProcedure         Tag = 0x36
+	TagRestrictType           Tag = 0x37
+	TagInterfaceType          Tag = 0x38
+	TagNamespace              Tag = 0x39
+	TagImportedModule         Tag = 0x3A
+	TagUnspecifiedType        Tag = 0x3B
+	TagPartialUnit            Tag = 0x3C
+	TagImportedUnit           Tag = 0x3D
+	TagMutableType            Tag = 0x3E
+)
+
+var tagNames = [...]string{
+	TagArrayType:              "ArrayType",
+	TagClassType:              "ClassType",
+	TagEntryPoint:             "EntryPoint",
+	TagEnumerationType:        "EnumerationType",
+	TagFormalParameter:        "FormalParameter",
+	TagImportedDeclaration:    "ImportedDeclaration",
+	TagLabel:                  "Label",
+	TagLexDwarfBlock:          "LexDwarfBlock",
+	TagMember:                 "Member",
+	TagPointerType:            "PointerType",
+	TagReferenceType:          "ReferenceType",
+	TagCompileUnit:            "CompileUnit",
+	TagStringType:             "StringType",
+	TagStructType:             "StructType",
+	TagSubroutineType:         "SubroutineType",
+	TagTypedef:                "Typedef",
+	TagUnionType:              "UnionType",
+	TagUnspecifiedParameters:  "UnspecifiedParameters",
+	TagVariant:                "Variant",
+	TagCommonDwarfBlock:       "CommonDwarfBlock",
+	TagCommonInclusion:        "CommonInclusion",
+	TagInheritance:            "Inheritance",
+	TagInlinedSubroutine:      "InlinedSubroutine",
+	TagModule:                 "Module",
+	TagPtrToMemberType:        "PtrToMemberType",
+	TagSetType:                "SetType",
+	TagSubrangeType:           "SubrangeType",
+	TagWithStmt:               "WithStmt",
+	TagAccessDeclaration:      "AccessDeclaration",
+	TagBaseType:               "BaseType",
+	TagCatchDwarfBlock:        "CatchDwarfBlock",
+	TagConstType:              "ConstType",
+	TagConstant:               "Constant",
+	TagEnumerator:             "Enumerator",
+	TagFileType:               "FileType",
+	TagFriend:                 "Friend",
+	TagNamelist:               "Namelist",
+	TagNamelistItem:           "NamelistItem",
+	TagPackedType:             "PackedType",
+	TagSubprogram:             "Subprogram",
+	TagTemplateTypeParameter:  "TemplateTypeParameter",
+	TagTemplateValueParameter: "TemplateValueParameter",
+	TagThrownType:             "ThrownType",
+	TagTryDwarfBlock:          "TryDwarfBlock",
+	TagVariantPart:            "VariantPart",
+	TagVariable:               "Variable",
+	TagVolatileType:           "VolatileType",
+	TagDwarfProcedure:         "DwarfProcedure",
+	TagRestrictType:           "RestrictType",
+	TagInterfaceType:          "InterfaceType",
+	TagNamespace:              "Namespace",
+	TagImportedModule:         "ImportedModule",
+	TagUnspecifiedType:        "UnspecifiedType",
+	TagPartialUnit:            "PartialUnit",
+	TagImportedUnit:           "ImportedUnit",
+	TagMutableType:            "MutableType",
+}
+
+func (t Tag) String() string {
+	if int(t) < len(tagNames) {
+		s := tagNames[t]
+		if s != "" {
+			return s
+		}
+	}
+	return strconv.Itoa(int(t))
+}
+
+func (t Tag) GoString() string {
+	if int(t) < len(tagNames) {
+		s := tagNames[t]
+		if s != "" {
+			return "dwarf.Tag" + s
+		}
+	}
+	return "dwarf.Tag(" + strconv.Itoa64(int64(t)) + ")"
+}
+
+// Location expression operators.
+// The debug info encodes value locations like 8(R3)
+// as a sequence of these op codes.
+// This package does not implement full expressions;
+// the opPlusUconst operator is expected by the type parser.
+const (
+	opAddr       = 0x03 /* 1 op, const addr */
+	opDeref      = 0x06
+	opConst1u    = 0x08 /* 1 op, 1 byte const */
+	opConst1s    = 0x09 /*	" signed */
+	opConst2u    = 0x0A /* 1 op, 2 byte const  */
+	opConst2s    = 0x0B /*	" signed */
+	opConst4u    = 0x0C /* 1 op, 4 byte const */
+	opConst4s    = 0x0D /*	" signed */
+	opConst8u    = 0x0E /* 1 op, 8 byte const */
+	opConst8s    = 0x0F /*	" signed */
+	opConstu     = 0x10 /* 1 op, LEB128 const */
+	opConsts     = 0x11 /*	" signed */
+	opDup        = 0x12
+	opDrop       = 0x13
+	opOver       = 0x14
+	opPick       = 0x15 /* 1 op, 1 byte stack index */
+	opSwap       = 0x16
+	opRot        = 0x17
+	opXderef     = 0x18
+	opAbs        = 0x19
+	opAnd        = 0x1A
+	opDiv        = 0x1B
+	opMinus      = 0x1C
+	opMod        = 0x1D
+	opMul        = 0x1E
+	opNeg        = 0x1F
+	opNot        = 0x20
+	opOr         = 0x21
+	opPlus       = 0x22
+	opPlusUconst = 0x23 /* 1 op, ULEB128 addend */
+	opShl        = 0x24
+	opShr        = 0x25
+	opShra       = 0x26
+	opXor        = 0x27
+	opSkip       = 0x2F /* 1 op, signed 2-byte constant */
+	opBra        = 0x28 /* 1 op, signed 2-byte constant */
+	opEq         = 0x29
+	opGe         = 0x2A
+	opGt         = 0x2B
+	opLe         = 0x2C
+	opLt         = 0x2D
+	opNe         = 0x2E
+	opLit0       = 0x30
+	/* OpLitN = OpLit0 + N for N = 0..31 */
+	opReg0 = 0x50
+	/* OpRegN = OpReg0 + N for N = 0..31 */
+	opBreg0 = 0x70 /* 1 op, signed LEB128 constant */
+	/* OpBregN = OpBreg0 + N for N = 0..31 */
+	opRegx       = 0x90 /* 1 op, ULEB128 register */
+	opFbreg      = 0x91 /* 1 op, SLEB128 offset */
+	opBregx      = 0x92 /* 2 op, ULEB128 reg; SLEB128 off */
+	opPiece      = 0x93 /* 1 op, ULEB128 size of piece */
+	opDerefSize  = 0x94 /* 1-byte size of data retrieved */
+	opXderefSize = 0x95 /* 1-byte size of data retrieved */
+	opNop        = 0x96
+	/* next four new in Dwarf v3 */
+	opPushObjAddr = 0x97
+	opCall2       = 0x98 /* 2-byte offset of DIE */
+	opCall4       = 0x99 /* 4-byte offset of DIE */
+	opCallRef     = 0x9A /* 4- or 8- byte offset of DIE */
+	/* 0xE0-0xFF reserved for user-specific */
+)
+
+// Basic type encodings -- the value for AttrEncoding in a TagBaseType Entry.
+const (
+	encAddress        = 0x01
+	encBoolean        = 0x02
+	encComplexFloat   = 0x03
+	encFloat          = 0x04
+	encSigned         = 0x05
+	encSignedChar     = 0x06
+	encUnsigned       = 0x07
+	encUnsignedChar   = 0x08
+	encImaginaryFloat = 0x09
+)
diff --git a/libgo/go/debug/dwarf/entry.go b/libgo/go/debug/dwarf/entry.go
new file mode 100644
index 000000000..549e5c2cc
--- /dev/null
+++ b/libgo/go/debug/dwarf/entry.go
@@ -0,0 +1,343 @@
+// 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.
+
+// DWARF debug information entry parser.
+// An entry is a sequence of data items of a given format.
+// The first word in the entry is an index into what DWARF
+// calls the ``abbreviation table.''  An abbreviation is really
+// just a type descriptor: it's an array of attribute tag/value format pairs.
+
+package dwarf
+
+import "os"
+
+// a single entry's description: a sequence of attributes
+type abbrev struct {
+	tag      Tag
+	children bool
+	field    []afield
+}
+
+type afield struct {
+	attr Attr
+	fmt  format
+}
+
+// a map from entry format ids to their descriptions
+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) {
+	if m, ok := d.abbrevCache[off]; ok {
+		return m, nil
+	}
+
+	data := d.abbrev
+	if off > uint32(len(data)) {
+		data = nil
+	} else {
+		data = data[off:]
+	}
+	b := makeBuf(d, "abbrev", 0, data, 0)
+
+	// Error handling is simplified by the buf getters
+	// returning an endless stream of 0s after an error.
+	m := make(abbrevTable)
+	for {
+		// Table ends with id == 0.
+		id := uint32(b.uint())
+		if id == 0 {
+			break
+		}
+
+		// Walk over attributes, counting.
+		n := 0
+		b1 := b // Read from copy of b.
+		b1.uint()
+		b1.uint8()
+		for {
+			tag := b1.uint()
+			fmt := b1.uint()
+			if tag == 0 && fmt == 0 {
+				break
+			}
+			n++
+		}
+		if b1.err != nil {
+			return nil, b1.err
+		}
+
+		// Walk over attributes again, this time writing them down.
+		var a abbrev
+		a.tag = Tag(b.uint())
+		a.children = b.uint8() != 0
+		a.field = make([]afield, n)
+		for i := range a.field {
+			a.field[i].attr = Attr(b.uint())
+			a.field[i].fmt = format(b.uint())
+		}
+		b.uint()
+		b.uint()
+
+		m[id] = a
+	}
+	if b.err != nil {
+		return nil, b.err
+	}
+	d.abbrevCache[off] = m
+	return m, nil
+}
+
+// An entry is a sequence of attribute/value pairs.
+type Entry struct {
+	Offset   Offset // offset of Entry in DWARF info
+	Tag      Tag    // tag (kind of Entry)
+	Children bool   // whether Entry is followed by children
+	Field    []Field
+}
+
+// A Field is a single attribute/value pair in an Entry.
+type Field struct {
+	Attr Attr
+	Val  interface{}
+}
+
+// Val returns the value associated with attribute Attr in Entry,
+// or nil if there is no such attribute.
+//
+// A common idiom is to merge the check for nil return with
+// the check that the value has the expected dynamic type, as in:
+//	v, ok := e.Val(AttrSibling).(int64);
+//
+func (e *Entry) Val(a Attr) interface{} {
+	for _, f := range e.Field {
+		if f.Attr == a {
+			return f.Val
+		}
+	}
+	return nil
+}
+
+// An Offset represents the location of an Entry within the DWARF info.
+// (See Reader.Seek.)
+type Offset uint32
+
+// Entry reads a single entry from buf, decoding
+// according to the given abbreviation table.
+func (b *buf) entry(atab abbrevTable, ubase Offset) *Entry {
+	off := b.off
+	id := uint32(b.uint())
+	if id == 0 {
+		return &Entry{}
+	}
+	a, ok := atab[id]
+	if !ok {
+		b.error("unknown abbreviation table index")
+		return nil
+	}
+	e := &Entry{
+		Offset:   off,
+		Tag:      a.tag,
+		Children: a.children,
+		Field:    make([]Field, len(a.field)),
+	}
+	for i := range e.Field {
+		e.Field[i].Attr = a.field[i].attr
+		fmt := a.field[i].fmt
+		if fmt == formIndirect {
+			fmt = format(b.uint())
+		}
+		var val interface{}
+		switch fmt {
+		default:
+			b.error("unknown entry attr format")
+
+		// address
+		case formAddr:
+			val = b.addr()
+
+		// block
+		case formDwarfBlock1:
+			val = b.bytes(int(b.uint8()))
+		case formDwarfBlock2:
+			val = b.bytes(int(b.uint16()))
+		case formDwarfBlock4:
+			val = b.bytes(int(b.uint32()))
+		case formDwarfBlock:
+			val = b.bytes(int(b.uint()))
+
+		// constant
+		case formData1:
+			val = int64(b.uint8())
+		case formData2:
+			val = int64(b.uint16())
+		case formData4:
+			val = int64(b.uint32())
+		case formData8:
+			val = int64(b.uint64())
+		case formSdata:
+			val = int64(b.int())
+		case formUdata:
+			val = int64(b.uint())
+
+		// flag
+		case formFlag:
+			val = b.uint8() == 1
+
+		// reference to other entry
+		case formRefAddr:
+			val = Offset(b.addr())
+		case formRef1:
+			val = Offset(b.uint8()) + ubase
+		case formRef2:
+			val = Offset(b.uint16()) + ubase
+		case formRef4:
+			val = Offset(b.uint32()) + ubase
+		case formRef8:
+			val = Offset(b.uint64()) + ubase
+		case formRefUdata:
+			val = Offset(b.uint()) + ubase
+
+		// string
+		case formString:
+			val = b.string()
+		case formStrp:
+			off := b.uint32() // offset into .debug_str
+			if b.err != nil {
+				return nil
+			}
+			b1 := makeBuf(b.dwarf, "str", 0, b.dwarf.str, 0)
+			b1.skip(int(off))
+			val = b1.string()
+			if b1.err != nil {
+				b.err = b1.err
+				return nil
+			}
+		}
+		e.Field[i].Val = val
+	}
+	if b.err != nil {
+		return nil
+	}
+	return e
+}
+
+// A Reader allows reading Entry structures from a DWARF ``info'' section.
+// The Entry structures are arranged in a tree.  The Reader's Next function
+// return successive entries from a pre-order traversal of the tree.
+// If an entry has children, its Children field will be true, and the children
+// follow, terminated by an Entry with Tag 0.
+type Reader struct {
+	b            buf
+	d            *Data
+	err          os.Error
+	unit         int
+	lastChildren bool   // .Children of last entry returned by Next
+	lastSibling  Offset // .Val(AttrSibling) of last entry returned by Next
+}
+
+// Reader returns a new Reader for Data.
+// The reader is positioned at byte offset 0 in the DWARF ``info'' section.
+func (d *Data) Reader() *Reader {
+	r := &Reader{d: d}
+	r.Seek(0)
+	return r
+}
+
+// Seek positions the Reader at offset off in the encoded entry stream.
+// Offset 0 can be used to denote the first entry.
+func (r *Reader) Seek(off Offset) {
+	d := r.d
+	r.err = nil
+	r.lastChildren = false
+	if off == 0 {
+		if len(d.unit) == 0 {
+			return
+		}
+		u := &d.unit[0]
+		r.unit = 0
+		r.b = makeBuf(r.d, "info", u.off, u.data, u.addrsize)
+		return
+	}
+
+	// TODO(rsc): binary search (maybe a new package)
+	var i int
+	var u *unit
+	for i = range d.unit {
+		u = &d.unit[i]
+		if u.off <= off && off < u.off+Offset(len(u.data)) {
+			r.unit = i
+			r.b = makeBuf(r.d, "info", off, u.data[off-u.off:], u.addrsize)
+			return
+		}
+	}
+	r.err = os.NewError("offset out of range")
+}
+
+// maybeNextUnit advances to the next unit if this one is finished.
+func (r *Reader) maybeNextUnit() {
+	for len(r.b.data) == 0 && r.unit+1 < len(r.d.unit) {
+		r.unit++
+		u := &r.d.unit[r.unit]
+		r.b = makeBuf(r.d, "info", u.off, u.data, u.addrsize)
+	}
+}
+
+// Next reads the next entry from the encoded entry stream.
+// 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) {
+	if r.err != nil {
+		return nil, r.err
+	}
+	r.maybeNextUnit()
+	if len(r.b.data) == 0 {
+		return nil, nil
+	}
+	u := &r.d.unit[r.unit]
+	e := r.b.entry(u.atable, u.base)
+	if r.b.err != nil {
+		r.err = r.b.err
+		return nil, r.err
+	}
+	if e != nil {
+		r.lastChildren = e.Children
+		if r.lastChildren {
+			r.lastSibling, _ = e.Val(AttrSibling).(Offset)
+		}
+	} else {
+		r.lastChildren = false
+	}
+	return e, nil
+}
+
+// SkipChildren skips over the child entries associated with
+// the last Entry returned by Next.  If that Entry did not have
+// children or Next has not been called, SkipChildren is a no-op.
+func (r *Reader) SkipChildren() {
+	if r.err != nil || !r.lastChildren {
+		return
+	}
+
+	// If the last entry had a sibling attribute,
+	// that attribute gives the offset of the next
+	// sibling, so we can avoid decoding the
+	// child subtrees.
+	if r.lastSibling >= r.b.off {
+		r.Seek(r.lastSibling)
+		return
+	}
+
+	for {
+		e, err := r.Next()
+		if err != nil || e == nil || e.Tag == 0 {
+			break
+		}
+		if e.Children {
+			r.SkipChildren()
+		}
+	}
+}
diff --git a/libgo/go/debug/dwarf/open.go b/libgo/go/debug/dwarf/open.go
new file mode 100644
index 000000000..cb009e0e0
--- /dev/null
+++ b/libgo/go/debug/dwarf/open.go
@@ -0,0 +1,80 @@
+// 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.
+
+// This package provides access to DWARF debugging information
+// loaded from executable files, as defined in the DWARF 2.0 Standard
+// at http://dwarfstd.org/doc/dwarf-2.0.0.pdf
+package dwarf
+
+import (
+	"encoding/binary"
+	"os"
+)
+
+// Data represents the DWARF debugging information
+// loaded from an executable file (for example, an ELF or Mach-O executable).
+type Data struct {
+	// raw data
+	abbrev   []byte
+	aranges  []byte
+	frame    []byte
+	info     []byte
+	line     []byte
+	pubnames []byte
+	ranges   []byte
+	str      []byte
+
+	// parsed data
+	abbrevCache map[uint32]abbrevTable
+	addrsize    int
+	order       binary.ByteOrder
+	typeCache   map[Offset]Type
+	unit        []unit
+}
+
+// New returns a new Data object initialized from the given parameters.
+// Clients should typically use [TODO(rsc): method to be named later] instead of calling
+// New directly.
+//
+// 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) {
+	d := &Data{
+		abbrev:      abbrev,
+		aranges:     aranges,
+		frame:       frame,
+		info:        info,
+		line:        line,
+		pubnames:    pubnames,
+		ranges:      ranges,
+		str:         str,
+		abbrevCache: make(map[uint32]abbrevTable),
+		typeCache:   make(map[Offset]Type),
+	}
+
+	// Sniff .debug_info to figure out byte order.
+	// bytes 4:6 are the version, a tiny 16-bit number (1, 2, 3).
+	if len(d.info) < 6 {
+		return nil, DecodeError{"info", Offset(len(d.info)), "too short"}
+	}
+	x, y := d.info[4], d.info[5]
+	switch {
+	case x == 0 && y == 0:
+		return nil, DecodeError{"info", 4, "unsupported version 0"}
+	case x == 0:
+		d.order = binary.BigEndian
+	case y == 0:
+		d.order = binary.LittleEndian
+	default:
+		return nil, DecodeError{"info", 4, "cannot determine byte order"}
+	}
+
+	u, err := d.parseUnits()
+	if err != nil {
+		return nil, err
+	}
+	d.unit = u
+	return d, nil
+}
diff --git a/libgo/go/debug/dwarf/testdata/typedef.c b/libgo/go/debug/dwarf/testdata/typedef.c
new file mode 100644
index 000000000..664d021ce
--- /dev/null
+++ b/libgo/go/debug/dwarf/testdata/typedef.c
@@ -0,0 +1,79 @@
+// 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.
+
+/*
+Linux ELF:
+gcc -gdwarf-2 -m64 -c typedef.c && gcc -gdwarf-2 -m64 -o typedef.elf typedef.o
+
+OS X Mach-O:
+gcc -gdwarf-2 -m64 -c typedef.c -o typedef.macho
+*/
+#include <complex.h>
+
+typedef volatile int* t_ptr_volatile_int;
+typedef const char *t_ptr_const_char;
+typedef long t_long;
+typedef unsigned short t_ushort;
+typedef int t_func_int_of_float_double(float, double);
+typedef int (*t_ptr_func_int_of_float_double)(float, double);
+typedef int (*t_ptr_func_int_of_float_complex)(float complex);
+typedef int (*t_ptr_func_int_of_double_complex)(double complex);
+typedef int (*t_ptr_func_int_of_long_double_complex)(long double complex);
+typedef int *t_func_ptr_int_of_char_schar_uchar(char, signed char, unsigned char);
+typedef void t_func_void_of_char(char);
+typedef void t_func_void_of_void(void);
+typedef void t_func_void_of_ptr_char_dots(char*, ...);
+typedef struct my_struct {
+	volatile int vi;
+	char x : 1;
+	int y : 4;
+	long long array[40];
+} t_my_struct;
+typedef union my_union {
+	volatile int vi;
+	char x : 1;
+	int y : 4;
+	long long array[40];
+} t_my_union;
+typedef enum my_enum {
+	e1 = 1,
+	e2 = 2,
+	e3 = -5,
+	e4 = 1000000000000000LL,
+} t_my_enum;
+
+typedef struct list t_my_list;
+struct list {
+	short val;
+	t_my_list *next;
+};
+
+typedef struct tree {
+	struct tree *left, *right;
+	unsigned long long val;
+} t_my_tree;
+
+t_ptr_volatile_int *a2;
+t_ptr_const_char **a3a;
+t_long *a4;
+t_ushort *a5;
+t_func_int_of_float_double *a6;
+t_ptr_func_int_of_float_double *a7;
+t_func_ptr_int_of_char_schar_uchar *a8;
+t_func_void_of_char *a9;
+t_func_void_of_void *a10;
+t_func_void_of_ptr_char_dots *a11;
+t_my_struct *a12;
+t_my_union *a12a;
+t_my_enum *a13;
+t_my_list *a14;
+t_my_tree *a15;
+t_ptr_func_int_of_float_complex *a16;
+t_ptr_func_int_of_double_complex *a17;
+t_ptr_func_int_of_long_double_complex *a18;
+
+int main()
+{
+	return 0;
+}
diff --git a/libgo/go/debug/dwarf/testdata/typedef.elf b/libgo/go/debug/dwarf/testdata/typedef.elf
new file mode 100755
index 000000000..44df8da9b
--- /dev/null
+++ b/libgo/go/debug/dwarf/testdata/typedef.elf
diff --git a/libgo/go/debug/dwarf/testdata/typedef.macho b/libgo/go/debug/dwarf/testdata/typedef.macho
new file mode 100644
index 000000000..41019c1e1
--- /dev/null
+++ b/libgo/go/debug/dwarf/testdata/typedef.macho
diff --git a/libgo/go/debug/dwarf/type.go b/libgo/go/debug/dwarf/type.go
new file mode 100644
index 000000000..902a545f8
--- /dev/null
+++ b/libgo/go/debug/dwarf/type.go
@@ -0,0 +1,583 @@
+// 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.
+
+// DWARF type information structures.
+// The format is heavily biased toward C, but for simplicity
+// the String methods use a pseudo-Go syntax.
+
+package dwarf
+
+import (
+	"os"
+	"strconv"
+)
+
+// A Type conventionally represents a pointer to any of the
+// specific Type structures (CharType, StructType, etc.).
+type Type interface {
+	Common() *CommonType
+	String() string
+	Size() int64
+}
+
+// A CommonType holds fields common to multiple types.
+// If a field is not known or not applicable for a given type,
+// the zero value is used.
+type CommonType struct {
+	ByteSize int64  // size of value of this type, in bytes
+	Name     string // name that can be used to refer to type
+}
+
+func (c *CommonType) Common() *CommonType { return c }
+
+func (c *CommonType) Size() int64 { return c.ByteSize }
+
+// Basic types
+
+// A BasicType holds fields common to all basic types.
+type BasicType struct {
+	CommonType
+	BitSize   int64
+	BitOffset int64
+}
+
+func (b *BasicType) Basic() *BasicType { return b }
+
+func (t *BasicType) String() string {
+	if t.Name != "" {
+		return t.Name
+	}
+	return "?"
+}
+
+// A CharType represents a signed character type.
+type CharType struct {
+	BasicType
+}
+
+// A UcharType represents an unsigned character type.
+type UcharType struct {
+	BasicType
+}
+
+// An IntType represents a signed integer type.
+type IntType struct {
+	BasicType
+}
+
+// A UintType represents an unsigned integer type.
+type UintType struct {
+	BasicType
+}
+
+// A FloatType represents a floating point type.
+type FloatType struct {
+	BasicType
+}
+
+// A ComplexType represents a complex floating point type.
+type ComplexType struct {
+	BasicType
+}
+
+// A BoolType represents a boolean type.
+type BoolType struct {
+	BasicType
+}
+
+// An AddrType represents a machine address type.
+type AddrType struct {
+	BasicType
+}
+
+// qualifiers
+
+// A QualType represents a type that has the C/C++ "const", "restrict", or "volatile" qualifier.
+type QualType struct {
+	CommonType
+	Qual string
+	Type Type
+}
+
+func (t *QualType) String() string { return t.Qual + " " + t.Type.String() }
+
+func (t *QualType) Size() int64 { return t.Type.Size() }
+
+// An ArrayType represents a fixed size array type.
+type ArrayType struct {
+	CommonType
+	Type          Type
+	StrideBitSize int64 // if > 0, number of bits to hold each element
+	Count         int64 // if == -1, an incomplete array, like char x[].
+}
+
+func (t *ArrayType) String() string {
+	return "[" + strconv.Itoa64(t.Count) + "]" + t.Type.String()
+}
+
+func (t *ArrayType) Size() int64 { return t.Count * t.Type.Size() }
+
+// A VoidType represents the C void type.
+type VoidType struct {
+	CommonType
+}
+
+func (t *VoidType) String() string { return "void" }
+
+// A PtrType represents a pointer type.
+type PtrType struct {
+	CommonType
+	Type Type
+}
+
+func (t *PtrType) String() string { return "*" + t.Type.String() }
+
+// A StructType represents a struct, union, or C++ class type.
+type StructType struct {
+	CommonType
+	StructName string
+	Kind       string // "struct", "union", or "class".
+	Field      []*StructField
+	Incomplete bool // if true, struct, union, class is declared but not defined
+}
+
+// A StructField represents a field in a struct, union, or C++ class type.
+type StructField struct {
+	Name       string
+	Type       Type
+	ByteOffset int64
+	ByteSize   int64
+	BitOffset  int64 // within the ByteSize bytes at ByteOffset
+	BitSize    int64 // zero if not a bit field
+}
+
+func (t *StructType) String() string {
+	if t.StructName != "" {
+		return t.Kind + " " + t.StructName
+	}
+	return t.Defn()
+}
+
+func (t *StructType) Defn() string {
+	s := t.Kind
+	if t.StructName != "" {
+		s += " " + t.StructName
+	}
+	if t.Incomplete {
+		s += " /*incomplete*/"
+		return s
+	}
+	s += " {"
+	for i, f := range t.Field {
+		if i > 0 {
+			s += "; "
+		}
+		s += f.Name + " " + f.Type.String()
+		s += "@" + strconv.Itoa64(f.ByteOffset)
+		if f.BitSize > 0 {
+			s += " : " + strconv.Itoa64(f.BitSize)
+			s += "@" + strconv.Itoa64(f.BitOffset)
+		}
+	}
+	s += "}"
+	return s
+}
+
+// An EnumType represents an enumerated type.
+// The only indication of its native integer type is its ByteSize
+// (inside CommonType).
+type EnumType struct {
+	CommonType
+	EnumName string
+	Val      []*EnumValue
+}
+
+// An EnumValue represents a single enumeration value.
+type EnumValue struct {
+	Name string
+	Val  int64
+}
+
+func (t *EnumType) String() string {
+	s := "enum"
+	if t.EnumName != "" {
+		s += " " + t.EnumName
+	}
+	s += " {"
+	for i, v := range t.Val {
+		if i > 0 {
+			s += "; "
+		}
+		s += v.Name + "=" + strconv.Itoa64(v.Val)
+	}
+	s += "}"
+	return s
+}
+
+// A FuncType represents a function type.
+type FuncType struct {
+	CommonType
+	ReturnType Type
+	ParamType  []Type
+}
+
+func (t *FuncType) String() string {
+	s := "func("
+	for i, t := range t.ParamType {
+		if i > 0 {
+			s += ", "
+		}
+		s += t.String()
+	}
+	s += ")"
+	if t.ReturnType != nil {
+		s += " " + t.ReturnType.String()
+	}
+	return s
+}
+
+// A DotDotDotType represents the variadic ... function parameter.
+type DotDotDotType struct {
+	CommonType
+}
+
+func (t *DotDotDotType) String() string { return "..." }
+
+// A TypedefType represents a named type.
+type TypedefType struct {
+	CommonType
+	Type Type
+}
+
+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) {
+	if t, ok := d.typeCache[off]; ok {
+		return t, nil
+	}
+
+	r := d.Reader()
+	r.Seek(off)
+	e, err := r.Next()
+	if err != nil {
+		return nil, err
+	}
+	if e == nil || e.Offset != off {
+		return nil, DecodeError{"info", off, "no type at offset"}
+	}
+
+	// Parse type from Entry.
+	// Must always set d.typeCache[off] before calling
+	// d.Type recursively, to handle circular types correctly.
+	var typ Type
+
+	// Get next child; set err if error happens.
+	next := func() *Entry {
+		if !e.Children {
+			return nil
+		}
+		kid, err1 := r.Next()
+		if err1 != nil {
+			err = err1
+			return nil
+		}
+		if kid == nil {
+			err = DecodeError{"info", r.b.off, "unexpected end of DWARF entries"}
+			return nil
+		}
+		if kid.Tag == 0 {
+			return nil
+		}
+		return kid
+	}
+
+	// Get Type referred to by Entry's AttrType field.
+	// Set err if error happens.  Not having a type is an error.
+	typeOf := func(e *Entry) Type {
+		toff, ok := e.Val(AttrType).(Offset)
+		if !ok {
+			// It appears that no Type means "void".
+			return new(VoidType)
+		}
+		var t Type
+		if t, err = d.Type(toff); err != nil {
+			return nil
+		}
+		return t
+	}
+
+	switch e.Tag {
+	case TagArrayType:
+		// Multi-dimensional array.  (DWARF v2 §5.4)
+		// Attributes:
+		//	AttrType:subtype [required]
+		//	AttrStrideSize: size in bits of each element of the array
+		//	AttrByteSize: size of entire array
+		// Children:
+		//	TagSubrangeType or TagEnumerationType giving one dimension.
+		//	dimensions are in left to right order.
+		t := new(ArrayType)
+		typ = t
+		d.typeCache[off] = t
+		if t.Type = typeOf(e); err != nil {
+			goto Error
+		}
+		t.StrideBitSize, _ = e.Val(AttrStrideSize).(int64)
+
+		// Accumulate dimensions,
+		ndim := 0
+		for kid := next(); kid != nil; kid = next() {
+			// TODO(rsc): Can also be TagEnumerationType
+			// but haven't seen that in the wild yet.
+			switch kid.Tag {
+			case TagSubrangeType:
+				max, ok := kid.Val(AttrUpperBound).(int64)
+				if !ok {
+					max = -2 // Count == -1, as in x[].
+				}
+				if ndim == 0 {
+					t.Count = max + 1
+				} else {
+					// Multidimensional array.
+					// Create new array type underneath this one.
+					t.Type = &ArrayType{Type: t.Type, Count: max + 1}
+				}
+				ndim++
+			case TagEnumerationType:
+				err = DecodeError{"info", kid.Offset, "cannot handle enumeration type as array bound"}
+				goto Error
+			}
+		}
+		if ndim == 0 {
+			err = DecodeError{"info", e.Offset, "missing dimension for array"}
+			goto Error
+		}
+
+	case TagBaseType:
+		// Basic type.  (DWARF v2 §5.1)
+		// Attributes:
+		//	AttrName: name of base type in programming language of the compilation unit [required]
+		//	AttrEncoding: encoding value for type (encFloat etc) [required]
+		//	AttrByteSize: size of type in bytes [required]
+		//	AttrBitOffset: for sub-byte types, size in bits
+		//	AttrBitSize: for sub-byte types, bit offset of high order bit in the AttrByteSize bytes
+		name, _ := e.Val(AttrName).(string)
+		enc, ok := e.Val(AttrEncoding).(int64)
+		if !ok {
+			err = DecodeError{"info", e.Offset, "missing encoding attribute for " + name}
+			goto Error
+		}
+		switch enc {
+		default:
+			err = DecodeError{"info", e.Offset, "unrecognized encoding attribute value"}
+			goto Error
+
+		case encAddress:
+			typ = new(AddrType)
+		case encBoolean:
+			typ = new(BoolType)
+		case encComplexFloat:
+			typ = new(ComplexType)
+		case encFloat:
+			typ = new(FloatType)
+		case encSigned:
+			typ = new(IntType)
+		case encUnsigned:
+			typ = new(UintType)
+		case encSignedChar:
+			typ = new(CharType)
+		case encUnsignedChar:
+			typ = new(UcharType)
+		}
+		d.typeCache[off] = typ
+		t := typ.(interface {
+			Basic() *BasicType
+		}).Basic()
+		t.Name = name
+		t.BitSize, _ = e.Val(AttrBitSize).(int64)
+		t.BitOffset, _ = e.Val(AttrBitOffset).(int64)
+
+	case TagClassType, TagStructType, TagUnionType:
+		// Structure, union, or class type.  (DWARF v2 §5.5)
+		// Attributes:
+		//	AttrName: name of struct, union, or class
+		//	AttrByteSize: byte size [required]
+		//	AttrDeclaration: if true, struct/union/class is incomplete
+		// Children:
+		//	TagMember to describe one member.
+		//		AttrName: name of member [required]
+		//		AttrType: type of member [required]
+		//		AttrByteSize: size in bytes
+		//		AttrBitOffset: bit offset within bytes for bit fields
+		//		AttrBitSize: bit size for bit fields
+		//		AttrDataMemberLoc: location within struct [required for struct, class]
+		// There is much more to handle C++, all ignored for now.
+		t := new(StructType)
+		typ = t
+		d.typeCache[off] = t
+		switch e.Tag {
+		case TagClassType:
+			t.Kind = "class"
+		case TagStructType:
+			t.Kind = "struct"
+		case TagUnionType:
+			t.Kind = "union"
+		}
+		t.StructName, _ = e.Val(AttrName).(string)
+		t.Incomplete = e.Val(AttrDeclaration) != nil
+		t.Field = make([]*StructField, 0, 8)
+		for kid := next(); kid != nil; kid = next() {
+			if kid.Tag == TagMember {
+				f := new(StructField)
+				if f.Type = typeOf(kid); err != nil {
+					goto Error
+				}
+				if loc, ok := kid.Val(AttrDataMemberLoc).([]byte); ok {
+					b := makeBuf(d, "location", 0, loc, d.addrsize)
+					if b.uint8() != opPlusUconst {
+						err = DecodeError{"info", kid.Offset, "unexpected opcode"}
+						goto Error
+					}
+					f.ByteOffset = int64(b.uint())
+					if b.err != nil {
+						err = b.err
+						goto Error
+					}
+				}
+				f.Name, _ = kid.Val(AttrName).(string)
+				f.ByteSize, _ = kid.Val(AttrByteSize).(int64)
+				f.BitOffset, _ = kid.Val(AttrBitOffset).(int64)
+				f.BitSize, _ = kid.Val(AttrBitSize).(int64)
+				t.Field = append(t.Field, f)
+			}
+		}
+
+	case TagConstType, TagVolatileType, TagRestrictType:
+		// Type modifier (DWARF v2 §5.2)
+		// Attributes:
+		//	AttrType: subtype
+		t := new(QualType)
+		typ = t
+		d.typeCache[off] = t
+		if t.Type = typeOf(e); err != nil {
+			goto Error
+		}
+		switch e.Tag {
+		case TagConstType:
+			t.Qual = "const"
+		case TagRestrictType:
+			t.Qual = "restrict"
+		case TagVolatileType:
+			t.Qual = "volatile"
+		}
+
+	case TagEnumerationType:
+		// Enumeration type (DWARF v2 §5.6)
+		// Attributes:
+		//	AttrName: enum name if any
+		//	AttrByteSize: bytes required to represent largest value
+		// Children:
+		//	TagEnumerator:
+		//		AttrName: name of constant
+		//		AttrConstValue: value of constant
+		t := new(EnumType)
+		typ = t
+		d.typeCache[off] = t
+		t.EnumName, _ = e.Val(AttrName).(string)
+		t.Val = make([]*EnumValue, 0, 8)
+		for kid := next(); kid != nil; kid = next() {
+			if kid.Tag == TagEnumerator {
+				f := new(EnumValue)
+				f.Name, _ = kid.Val(AttrName).(string)
+				f.Val, _ = kid.Val(AttrConstValue).(int64)
+				n := len(t.Val)
+				if n >= cap(t.Val) {
+					val := make([]*EnumValue, n, n*2)
+					copy(val, t.Val)
+					t.Val = val
+				}
+				t.Val = t.Val[0 : n+1]
+				t.Val[n] = f
+			}
+		}
+
+	case TagPointerType:
+		// Type modifier (DWARF v2 §5.2)
+		// Attributes:
+		//	AttrType: subtype [not required!  void* has no AttrType]
+		//	AttrAddrClass: address class [ignored]
+		t := new(PtrType)
+		typ = t
+		d.typeCache[off] = t
+		if e.Val(AttrType) == nil {
+			t.Type = &VoidType{}
+			break
+		}
+		t.Type = typeOf(e)
+
+	case TagSubroutineType:
+		// Subroutine type.  (DWARF v2 §5.7)
+		// Attributes:
+		//	AttrType: type of return value if any
+		//	AttrName: possible name of type [ignored]
+		//	AttrPrototyped: whether used ANSI C prototye [ignored]
+		// Children:
+		//	TagFormalParameter: typed parameter
+		//		AttrType: type of parameter
+		//	TagUnspecifiedParameter: final ...
+		t := new(FuncType)
+		typ = t
+		d.typeCache[off] = t
+		if t.ReturnType = typeOf(e); err != nil {
+			goto Error
+		}
+		t.ParamType = make([]Type, 0, 8)
+		for kid := next(); kid != nil; kid = next() {
+			var tkid Type
+			switch kid.Tag {
+			default:
+				continue
+			case TagFormalParameter:
+				if tkid = typeOf(kid); err != nil {
+					goto Error
+				}
+			case TagUnspecifiedParameters:
+				tkid = &DotDotDotType{}
+			}
+			t.ParamType = append(t.ParamType, tkid)
+		}
+
+	case TagTypedef:
+		// Typedef (DWARF v2 §5.3)
+		// Attributes:
+		//	AttrName: name [required]
+		//	AttrType: type definition [required]
+		t := new(TypedefType)
+		typ = t
+		d.typeCache[off] = t
+		t.Name, _ = e.Val(AttrName).(string)
+		t.Type = typeOf(e)
+	}
+
+	if err != nil {
+		goto Error
+	}
+
+	b, ok := e.Val(AttrByteSize).(int64)
+	if !ok {
+		b = -1
+	}
+	typ.Common().ByteSize = b
+
+	return typ, nil
+
+Error:
+	// If the parse fails, take the type out of the cache
+	// so that the next call with this offset doesn't hit
+	// the cache and return success.
+	d.typeCache[off] = nil, false
+	return nil, err
+}
diff --git a/libgo/go/debug/dwarf/type_test.go b/libgo/go/debug/dwarf/type_test.go
new file mode 100644
index 000000000..e01f7353a
--- /dev/null
+++ b/libgo/go/debug/dwarf/type_test.go
@@ -0,0 +1,112 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package dwarf_test
+
+import (
+	. "debug/dwarf"
+	"debug/elf"
+	"debug/macho"
+	"testing"
+)
+
+var typedefTests = map[string]string{
+	"t_ptr_volatile_int":                    "*volatile int",
+	"t_ptr_const_char":                      "*const char",
+	"t_long":                                "long int",
+	"t_ushort":                              "short unsigned int",
+	"t_func_int_of_float_double":            "func(float, double) int",
+	"t_ptr_func_int_of_float_double":        "*func(float, double) int",
+	"t_ptr_func_int_of_float_complex":       "*func(complex float) int",
+	"t_ptr_func_int_of_double_complex":      "*func(complex double) int",
+	"t_ptr_func_int_of_long_double_complex": "*func(complex long double) int",
+	"t_func_ptr_int_of_char_schar_uchar":    "func(char, signed char, unsigned char) *int",
+	"t_func_void_of_char":                   "func(char) void",
+	"t_func_void_of_void":                   "func() void",
+	"t_func_void_of_ptr_char_dots":          "func(*char, ...) void",
+	"t_my_struct":                           "struct my_struct {vi volatile int@0; x char@4 : 1@7; y int@4 : 4@27; array [40]long long int@8}",
+	"t_my_union":                            "union my_union {vi volatile int@0; x char@0 : 1@7; y int@0 : 4@28; array [40]long long int@0}",
+	"t_my_enum":                             "enum my_enum {e1=1; e2=2; e3=-5; e4=1000000000000000}",
+	"t_my_list":                             "struct list {val short int@0; next *t_my_list@8}",
+	"t_my_tree":                             "struct tree {left *struct tree@0; right *struct tree@8; val long long unsigned int@16}",
+}
+
+func elfData(t *testing.T, name string) *Data {
+	f, err := elf.Open(name)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	d, err := f.DWARF()
+	if err != nil {
+		t.Fatal(err)
+	}
+	return d
+}
+
+func machoData(t *testing.T, name string) *Data {
+	f, err := macho.Open(name)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	d, err := f.DWARF()
+	if err != nil {
+		t.Fatal(err)
+	}
+	return d
+}
+
+
+func TestTypedefsELF(t *testing.T) { testTypedefs(t, elfData(t, "testdata/typedef.elf")) }
+
+func TestTypedefsMachO(t *testing.T) {
+	testTypedefs(t, machoData(t, "testdata/typedef.macho"))
+}
+
+func testTypedefs(t *testing.T, d *Data) {
+	r := d.Reader()
+	seen := make(map[string]bool)
+	for {
+		e, err := r.Next()
+		if err != nil {
+			t.Fatal("r.Next:", err)
+		}
+		if e == nil {
+			break
+		}
+		if e.Tag == TagTypedef {
+			typ, err := d.Type(e.Offset)
+			if err != nil {
+				t.Fatal("d.Type:", err)
+			}
+			t1 := typ.(*TypedefType)
+			var typstr string
+			if ts, ok := t1.Type.(*StructType); ok {
+				typstr = ts.Defn()
+			} else {
+				typstr = t1.Type.String()
+			}
+
+			if want, ok := typedefTests[t1.Name]; ok {
+				if seen[t1.Name] {
+					t.Errorf("multiple definitions for %s", t1.Name)
+				}
+				seen[t1.Name] = true
+				if typstr != want {
+					t.Errorf("%s:\n\thave %s\n\twant %s", t1.Name, typstr, want)
+				}
+			}
+		}
+		if e.Tag != TagCompileUnit {
+			r.SkipChildren()
+		}
+	}
+
+	for k := range typedefTests {
+		if !seen[k] {
+			t.Errorf("missing %s", k)
+		}
+	}
+}
diff --git a/libgo/go/debug/dwarf/unit.go b/libgo/go/debug/dwarf/unit.go
new file mode 100644
index 000000000..02cb363b4
--- /dev/null
+++ b/libgo/go/debug/dwarf/unit.go
@@ -0,0 +1,62 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package dwarf
+
+import (
+	"os"
+	"strconv"
+)
+
+// DWARF debug info is split into a sequence of compilation units.
+// Each unit has its own abbreviation table and address size.
+
+type unit struct {
+	base     Offset // byte offset of header within the aggregate info
+	off      Offset // byte offset of data within the aggregate info
+	data     []byte
+	atable   abbrevTable
+	addrsize int
+}
+
+func (d *Data) parseUnits() ([]unit, os.Error) {
+	// Count units.
+	nunit := 0
+	b := makeBuf(d, "info", 0, d.info, 0)
+	for len(b.data) > 0 {
+		b.skip(int(b.uint32()))
+		nunit++
+	}
+	if b.err != nil {
+		return nil, b.err
+	}
+
+	// Again, this time writing them down.
+	b = makeBuf(d, "info", 0, d.info, 0)
+	units := make([]unit, nunit)
+	for i := range units {
+		u := &units[i]
+		u.base = b.off
+		n := b.uint32()
+		if vers := b.uint16(); vers != 2 {
+			b.error("unsupported DWARF version " + strconv.Itoa(int(vers)))
+			break
+		}
+		atable, err := d.parseAbbrev(b.uint32())
+		if err != nil {
+			if b.err == nil {
+				b.err = err
+			}
+			break
+		}
+		u.atable = atable
+		u.addrsize = int(b.uint8())
+		u.off = b.off
+		u.data = b.bytes(int(n - (2 + 4 + 1)))
+	}
+	if b.err != nil {
+		return nil, b.err
+	}
+	return units, nil
+}
diff --git a/libgo/go/debug/elf/elf.go b/libgo/go/debug/elf/elf.go
new file mode 100644
index 000000000..74e979986
--- /dev/null
+++ b/libgo/go/debug/elf/elf.go
@@ -0,0 +1,1506 @@
+/*
+ * ELF constants and data structures
+ *
+ * Derived from:
+ * $FreeBSD: src/sys/sys/elf32.h,v 1.8.14.1 2005/12/30 22:13:58 marcel Exp $
+ * $FreeBSD: src/sys/sys/elf64.h,v 1.10.14.1 2005/12/30 22:13:58 marcel Exp $
+ * $FreeBSD: src/sys/sys/elf_common.h,v 1.15.8.1 2005/12/30 22:13:58 marcel Exp $
+ * $FreeBSD: src/sys/alpha/include/elf.h,v 1.14 2003/09/25 01:10:22 peter Exp $
+ * $FreeBSD: src/sys/amd64/include/elf.h,v 1.18 2004/08/03 08:21:48 dfr Exp $
+ * $FreeBSD: src/sys/arm/include/elf.h,v 1.5.2.1 2006/06/30 21:42:52 cognet Exp $
+ * $FreeBSD: src/sys/i386/include/elf.h,v 1.16 2004/08/02 19:12:17 dfr Exp $
+ * $FreeBSD: src/sys/powerpc/include/elf.h,v 1.7 2004/11/02 09:47:01 ssouhlal Exp $
+ * $FreeBSD: src/sys/sparc64/include/elf.h,v 1.12 2003/09/25 01:10:26 peter Exp $
+ *
+ * Copyright (c) 1996-1998 John D. Polstra.  All rights reserved.
+ * Copyright (c) 2001 David E. O'Brien
+ * Portions Copyright 2009 The Go Authors.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+package elf
+
+import "strconv"
+
+/*
+ * Constants
+ */
+
+// Indexes into the Header.Ident array.
+const (
+	EI_CLASS      = 4  /* Class of machine. */
+	EI_DATA       = 5  /* Data format. */
+	EI_VERSION    = 6  /* ELF format version. */
+	EI_OSABI      = 7  /* Operating system / ABI identification */
+	EI_ABIVERSION = 8  /* ABI version */
+	EI_PAD        = 9  /* Start of padding (per SVR4 ABI). */
+	EI_NIDENT     = 16 /* Size of e_ident array. */
+)
+
+// Initial magic number for ELF files.
+const ELFMAG = "\177ELF"
+
+// Version is found in Header.Ident[EI_VERSION] and Header.Version.
+type Version byte
+
+const (
+	EV_NONE    Version = 0
+	EV_CURRENT Version = 1
+)
+
+var versionStrings = []intName{
+	{0, "EV_NONE"},
+	{1, "EV_CURRENT"},
+}
+
+func (i Version) String() string   { return stringName(uint32(i), versionStrings, false) }
+func (i Version) GoString() string { return stringName(uint32(i), versionStrings, true) }
+
+// Class is found in Header.Ident[EI_CLASS] and Header.Class.
+type Class byte
+
+const (
+	ELFCLASSNONE Class = 0 /* Unknown class. */
+	ELFCLASS32   Class = 1 /* 32-bit architecture. */
+	ELFCLASS64   Class = 2 /* 64-bit architecture. */
+)
+
+var classStrings = []intName{
+	{0, "ELFCLASSNONE"},
+	{1, "ELFCLASS32"},
+	{2, "ELFCLASS64"},
+}
+
+func (i Class) String() string   { return stringName(uint32(i), classStrings, false) }
+func (i Class) GoString() string { return stringName(uint32(i), classStrings, true) }
+
+// Data is found in Header.Ident[EI_DATA] and Header.Data.
+type Data byte
+
+const (
+	ELFDATANONE Data = 0 /* Unknown data format. */
+	ELFDATA2LSB Data = 1 /* 2's complement little-endian. */
+	ELFDATA2MSB Data = 2 /* 2's complement big-endian. */
+)
+
+var dataStrings = []intName{
+	{0, "ELFDATANONE"},
+	{1, "ELFDATA2LSB"},
+	{2, "ELFDATA2MSB"},
+}
+
+func (i Data) String() string   { return stringName(uint32(i), dataStrings, false) }
+func (i Data) GoString() string { return stringName(uint32(i), dataStrings, true) }
+
+// OSABI is found in Header.Ident[EI_OSABI] and Header.OSABI.
+type OSABI byte
+
+const (
+	ELFOSABI_NONE       OSABI = 0   /* UNIX System V ABI */
+	ELFOSABI_HPUX       OSABI = 1   /* HP-UX operating system */
+	ELFOSABI_NETBSD     OSABI = 2   /* NetBSD */
+	ELFOSABI_LINUX      OSABI = 3   /* GNU/Linux */
+	ELFOSABI_HURD       OSABI = 4   /* GNU/Hurd */
+	ELFOSABI_86OPEN     OSABI = 5   /* 86Open common IA32 ABI */
+	ELFOSABI_SOLARIS    OSABI = 6   /* Solaris */
+	ELFOSABI_AIX        OSABI = 7   /* AIX */
+	ELFOSABI_IRIX       OSABI = 8   /* IRIX */
+	ELFOSABI_FREEBSD    OSABI = 9   /* FreeBSD */
+	ELFOSABI_TRU64      OSABI = 10  /* TRU64 UNIX */
+	ELFOSABI_MODESTO    OSABI = 11  /* Novell Modesto */
+	ELFOSABI_OPENBSD    OSABI = 12  /* OpenBSD */
+	ELFOSABI_OPENVMS    OSABI = 13  /* Open VMS */
+	ELFOSABI_NSK        OSABI = 14  /* HP Non-Stop Kernel */
+	ELFOSABI_ARM        OSABI = 97  /* ARM */
+	ELFOSABI_STANDALONE OSABI = 255 /* Standalone (embedded) application */
+)
+
+var osabiStrings = []intName{
+	{0, "ELFOSABI_NONE"},
+	{1, "ELFOSABI_HPUX"},
+	{2, "ELFOSABI_NETBSD"},
+	{3, "ELFOSABI_LINUX"},
+	{4, "ELFOSABI_HURD"},
+	{5, "ELFOSABI_86OPEN"},
+	{6, "ELFOSABI_SOLARIS"},
+	{7, "ELFOSABI_AIX"},
+	{8, "ELFOSABI_IRIX"},
+	{9, "ELFOSABI_FREEBSD"},
+	{10, "ELFOSABI_TRU64"},
+	{11, "ELFOSABI_MODESTO"},
+	{12, "ELFOSABI_OPENBSD"},
+	{13, "ELFOSABI_OPENVMS"},
+	{14, "ELFOSABI_NSK"},
+	{97, "ELFOSABI_ARM"},
+	{255, "ELFOSABI_STANDALONE"},
+}
+
+func (i OSABI) String() string   { return stringName(uint32(i), osabiStrings, false) }
+func (i OSABI) GoString() string { return stringName(uint32(i), osabiStrings, true) }
+
+// Type is found in Header.Type.
+type Type uint16
+
+const (
+	ET_NONE   Type = 0      /* Unknown type. */
+	ET_REL    Type = 1      /* Relocatable. */
+	ET_EXEC   Type = 2      /* Executable. */
+	ET_DYN    Type = 3      /* Shared object. */
+	ET_CORE   Type = 4      /* Core file. */
+	ET_LOOS   Type = 0xfe00 /* First operating system specific. */
+	ET_HIOS   Type = 0xfeff /* Last operating system-specific. */
+	ET_LOPROC Type = 0xff00 /* First processor-specific. */
+	ET_HIPROC Type = 0xffff /* Last processor-specific. */
+)
+
+var typeStrings = []intName{
+	{0, "ET_NONE"},
+	{1, "ET_REL"},
+	{2, "ET_EXEC"},
+	{3, "ET_DYN"},
+	{4, "ET_CORE"},
+	{0xfe00, "ET_LOOS"},
+	{0xfeff, "ET_HIOS"},
+	{0xff00, "ET_LOPROC"},
+	{0xffff, "ET_HIPROC"},
+}
+
+func (i Type) String() string   { return stringName(uint32(i), typeStrings, false) }
+func (i Type) GoString() string { return stringName(uint32(i), typeStrings, true) }
+
+// Machine is found in Header.Machine.
+type Machine uint16
+
+const (
+	EM_NONE        Machine = 0  /* Unknown machine. */
+	EM_M32         Machine = 1  /* AT&T WE32100. */
+	EM_SPARC       Machine = 2  /* Sun SPARC. */
+	EM_386         Machine = 3  /* Intel i386. */
+	EM_68K         Machine = 4  /* Motorola 68000. */
+	EM_88K         Machine = 5  /* Motorola 88000. */
+	EM_860         Machine = 7  /* Intel i860. */
+	EM_MIPS        Machine = 8  /* MIPS R3000 Big-Endian only. */
+	EM_S370        Machine = 9  /* IBM System/370. */
+	EM_MIPS_RS3_LE Machine = 10 /* MIPS R3000 Little-Endian. */
+	EM_PARISC      Machine = 15 /* HP PA-RISC. */
+	EM_VPP500      Machine = 17 /* Fujitsu VPP500. */
+	EM_SPARC32PLUS Machine = 18 /* SPARC v8plus. */
+	EM_960         Machine = 19 /* Intel 80960. */
+	EM_PPC         Machine = 20 /* PowerPC 32-bit. */
+	EM_PPC64       Machine = 21 /* PowerPC 64-bit. */
+	EM_S390        Machine = 22 /* IBM System/390. */
+	EM_V800        Machine = 36 /* NEC V800. */
+	EM_FR20        Machine = 37 /* Fujitsu FR20. */
+	EM_RH32        Machine = 38 /* TRW RH-32. */
+	EM_RCE         Machine = 39 /* Motorola RCE. */
+	EM_ARM         Machine = 40 /* ARM. */
+	EM_SH          Machine = 42 /* Hitachi SH. */
+	EM_SPARCV9     Machine = 43 /* SPARC v9 64-bit. */
+	EM_TRICORE     Machine = 44 /* Siemens TriCore embedded processor. */
+	EM_ARC         Machine = 45 /* Argonaut RISC Core. */
+	EM_H8_300      Machine = 46 /* Hitachi H8/300. */
+	EM_H8_300H     Machine = 47 /* Hitachi H8/300H. */
+	EM_H8S         Machine = 48 /* Hitachi H8S. */
+	EM_H8_500      Machine = 49 /* Hitachi H8/500. */
+	EM_IA_64       Machine = 50 /* Intel IA-64 Processor. */
+	EM_MIPS_X      Machine = 51 /* Stanford MIPS-X. */
+	EM_COLDFIRE    Machine = 52 /* Motorola ColdFire. */
+	EM_68HC12      Machine = 53 /* Motorola M68HC12. */
+	EM_MMA         Machine = 54 /* Fujitsu MMA. */
+	EM_PCP         Machine = 55 /* Siemens PCP. */
+	EM_NCPU        Machine = 56 /* Sony nCPU. */
+	EM_NDR1        Machine = 57 /* Denso NDR1 microprocessor. */
+	EM_STARCORE    Machine = 58 /* Motorola Star*Core processor. */
+	EM_ME16        Machine = 59 /* Toyota ME16 processor. */
+	EM_ST100       Machine = 60 /* STMicroelectronics ST100 processor. */
+	EM_TINYJ       Machine = 61 /* Advanced Logic Corp. TinyJ processor. */
+	EM_X86_64      Machine = 62 /* Advanced Micro Devices x86-64 */
+
+	/* Non-standard or deprecated. */
+	EM_486         Machine = 6      /* Intel i486. */
+	EM_MIPS_RS4_BE Machine = 10     /* MIPS R4000 Big-Endian */
+	EM_ALPHA_STD   Machine = 41     /* Digital Alpha (standard value). */
+	EM_ALPHA       Machine = 0x9026 /* Alpha (written in the absence of an ABI) */
+)
+
+var machineStrings = []intName{
+	{0, "EM_NONE"},
+	{1, "EM_M32"},
+	{2, "EM_SPARC"},
+	{3, "EM_386"},
+	{4, "EM_68K"},
+	{5, "EM_88K"},
+	{7, "EM_860"},
+	{8, "EM_MIPS"},
+	{9, "EM_S370"},
+	{10, "EM_MIPS_RS3_LE"},
+	{15, "EM_PARISC"},
+	{17, "EM_VPP500"},
+	{18, "EM_SPARC32PLUS"},
+	{19, "EM_960"},
+	{20, "EM_PPC"},
+	{21, "EM_PPC64"},
+	{22, "EM_S390"},
+	{36, "EM_V800"},
+	{37, "EM_FR20"},
+	{38, "EM_RH32"},
+	{39, "EM_RCE"},
+	{40, "EM_ARM"},
+	{42, "EM_SH"},
+	{43, "EM_SPARCV9"},
+	{44, "EM_TRICORE"},
+	{45, "EM_ARC"},
+	{46, "EM_H8_300"},
+	{47, "EM_H8_300H"},
+	{48, "EM_H8S"},
+	{49, "EM_H8_500"},
+	{50, "EM_IA_64"},
+	{51, "EM_MIPS_X"},
+	{52, "EM_COLDFIRE"},
+	{53, "EM_68HC12"},
+	{54, "EM_MMA"},
+	{55, "EM_PCP"},
+	{56, "EM_NCPU"},
+	{57, "EM_NDR1"},
+	{58, "EM_STARCORE"},
+	{59, "EM_ME16"},
+	{60, "EM_ST100"},
+	{61, "EM_TINYJ"},
+	{62, "EM_X86_64"},
+
+	/* Non-standard or deprecated. */
+	{6, "EM_486"},
+	{10, "EM_MIPS_RS4_BE"},
+	{41, "EM_ALPHA_STD"},
+	{0x9026, "EM_ALPHA"},
+}
+
+func (i Machine) String() string   { return stringName(uint32(i), machineStrings, false) }
+func (i Machine) GoString() string { return stringName(uint32(i), machineStrings, true) }
+
+// Special section indices.
+type SectionIndex int
+
+const (
+	SHN_UNDEF     SectionIndex = 0      /* Undefined, missing, irrelevant. */
+	SHN_LORESERVE SectionIndex = 0xff00 /* First of reserved range. */
+	SHN_LOPROC    SectionIndex = 0xff00 /* First processor-specific. */
+	SHN_HIPROC    SectionIndex = 0xff1f /* Last processor-specific. */
+	SHN_LOOS      SectionIndex = 0xff20 /* First operating system-specific. */
+	SHN_HIOS      SectionIndex = 0xff3f /* Last operating system-specific. */
+	SHN_ABS       SectionIndex = 0xfff1 /* Absolute values. */
+	SHN_COMMON    SectionIndex = 0xfff2 /* Common data. */
+	SHN_XINDEX    SectionIndex = 0xffff /* Escape -- index stored elsewhere. */
+	SHN_HIRESERVE SectionIndex = 0xffff /* Last of reserved range. */
+)
+
+var shnStrings = []intName{
+	{0, "SHN_UNDEF"},
+	{0xff00, "SHN_LOPROC"},
+	{0xff20, "SHN_LOOS"},
+	{0xfff1, "SHN_ABS"},
+	{0xfff2, "SHN_COMMON"},
+	{0xffff, "SHN_XINDEX"},
+}
+
+func (i SectionIndex) String() string   { return stringName(uint32(i), shnStrings, false) }
+func (i SectionIndex) GoString() string { return stringName(uint32(i), shnStrings, true) }
+
+// Section type.
+type SectionType uint32
+
+const (
+	SHT_NULL          SectionType = 0          /* inactive */
+	SHT_PROGBITS      SectionType = 1          /* program defined information */
+	SHT_SYMTAB        SectionType = 2          /* symbol table section */
+	SHT_STRTAB        SectionType = 3          /* string table section */
+	SHT_RELA          SectionType = 4          /* relocation section with addends */
+	SHT_HASH          SectionType = 5          /* symbol hash table section */
+	SHT_DYNAMIC       SectionType = 6          /* dynamic section */
+	SHT_NOTE          SectionType = 7          /* note section */
+	SHT_NOBITS        SectionType = 8          /* no space section */
+	SHT_REL           SectionType = 9          /* relocation section - no addends */
+	SHT_SHLIB         SectionType = 10         /* reserved - purpose unknown */
+	SHT_DYNSYM        SectionType = 11         /* dynamic symbol table section */
+	SHT_INIT_ARRAY    SectionType = 14         /* Initialization function pointers. */
+	SHT_FINI_ARRAY    SectionType = 15         /* Termination function pointers. */
+	SHT_PREINIT_ARRAY SectionType = 16         /* Pre-initialization function ptrs. */
+	SHT_GROUP         SectionType = 17         /* Section group. */
+	SHT_SYMTAB_SHNDX  SectionType = 18         /* Section indexes (see SHN_XINDEX). */
+	SHT_LOOS          SectionType = 0x60000000 /* First of OS specific semantics */
+	SHT_HIOS          SectionType = 0x6fffffff /* Last of OS specific semantics */
+	SHT_LOPROC        SectionType = 0x70000000 /* reserved range for processor */
+	SHT_HIPROC        SectionType = 0x7fffffff /* specific section header types */
+	SHT_LOUSER        SectionType = 0x80000000 /* reserved range for application */
+	SHT_HIUSER        SectionType = 0xffffffff /* specific indexes */
+)
+
+var shtStrings = []intName{
+	{0, "SHT_NULL"},
+	{1, "SHT_PROGBITS"},
+	{2, "SHT_SYMTAB"},
+	{3, "SHT_STRTAB"},
+	{4, "SHT_RELA"},
+	{5, "SHT_HASH"},
+	{6, "SHT_DYNAMIC"},
+	{7, "SHT_NOTE"},
+	{8, "SHT_NOBITS"},
+	{9, "SHT_REL"},
+	{10, "SHT_SHLIB"},
+	{11, "SHT_DYNSYM"},
+	{14, "SHT_INIT_ARRAY"},
+	{15, "SHT_FINI_ARRAY"},
+	{16, "SHT_PREINIT_ARRAY"},
+	{17, "SHT_GROUP"},
+	{18, "SHT_SYMTAB_SHNDX"},
+	{0x60000000, "SHT_LOOS"},
+	{0x6fffffff, "SHT_HIOS"},
+	{0x70000000, "SHT_LOPROC"},
+	{0x7fffffff, "SHT_HIPROC"},
+	{0x80000000, "SHT_LOUSER"},
+	{0xffffffff, "SHT_HIUSER"},
+}
+
+func (i SectionType) String() string   { return stringName(uint32(i), shtStrings, false) }
+func (i SectionType) GoString() string { return stringName(uint32(i), shtStrings, true) }
+
+// Section flags.
+type SectionFlag uint32
+
+const (
+	SHF_WRITE            SectionFlag = 0x1        /* Section contains writable data. */
+	SHF_ALLOC            SectionFlag = 0x2        /* Section occupies memory. */
+	SHF_EXECINSTR        SectionFlag = 0x4        /* Section contains instructions. */
+	SHF_MERGE            SectionFlag = 0x10       /* Section may be merged. */
+	SHF_STRINGS          SectionFlag = 0x20       /* Section contains strings. */
+	SHF_INFO_LINK        SectionFlag = 0x40       /* sh_info holds section index. */
+	SHF_LINK_ORDER       SectionFlag = 0x80       /* Special ordering requirements. */
+	SHF_OS_NONCONFORMING SectionFlag = 0x100      /* OS-specific processing required. */
+	SHF_GROUP            SectionFlag = 0x200      /* Member of section group. */
+	SHF_TLS              SectionFlag = 0x400      /* Section contains TLS data. */
+	SHF_MASKOS           SectionFlag = 0x0ff00000 /* OS-specific semantics. */
+	SHF_MASKPROC         SectionFlag = 0xf0000000 /* Processor-specific semantics. */
+)
+
+var shfStrings = []intName{
+	{0x1, "SHF_WRITE"},
+	{0x2, "SHF_ALLOC"},
+	{0x4, "SHF_EXECINSTR"},
+	{0x10, "SHF_MERGE"},
+	{0x20, "SHF_STRINGS"},
+	{0x40, "SHF_INFO_LINK"},
+	{0x80, "SHF_LINK_ORDER"},
+	{0x100, "SHF_OS_NONCONFORMING"},
+	{0x200, "SHF_GROUP"},
+	{0x400, "SHF_TLS"},
+}
+
+func (i SectionFlag) String() string   { return flagName(uint32(i), shfStrings, false) }
+func (i SectionFlag) GoString() string { return flagName(uint32(i), shfStrings, true) }
+
+// Prog.Type
+type ProgType int
+
+const (
+	PT_NULL    ProgType = 0          /* Unused entry. */
+	PT_LOAD    ProgType = 1          /* Loadable segment. */
+	PT_DYNAMIC ProgType = 2          /* Dynamic linking information segment. */
+	PT_INTERP  ProgType = 3          /* Pathname of interpreter. */
+	PT_NOTE    ProgType = 4          /* Auxiliary information. */
+	PT_SHLIB   ProgType = 5          /* Reserved (not used). */
+	PT_PHDR    ProgType = 6          /* Location of program header itself. */
+	PT_TLS     ProgType = 7          /* Thread local storage segment */
+	PT_LOOS    ProgType = 0x60000000 /* First OS-specific. */
+	PT_HIOS    ProgType = 0x6fffffff /* Last OS-specific. */
+	PT_LOPROC  ProgType = 0x70000000 /* First processor-specific type. */
+	PT_HIPROC  ProgType = 0x7fffffff /* Last processor-specific type. */
+)
+
+var ptStrings = []intName{
+	{0, "PT_NULL"},
+	{1, "PT_LOAD"},
+	{2, "PT_DYNAMIC"},
+	{3, "PT_INTERP"},
+	{4, "PT_NOTE"},
+	{5, "PT_SHLIB"},
+	{6, "PT_PHDR"},
+	{7, "PT_TLS"},
+	{0x60000000, "PT_LOOS"},
+	{0x6fffffff, "PT_HIOS"},
+	{0x70000000, "PT_LOPROC"},
+	{0x7fffffff, "PT_HIPROC"},
+}
+
+func (i ProgType) String() string   { return stringName(uint32(i), ptStrings, false) }
+func (i ProgType) GoString() string { return stringName(uint32(i), ptStrings, true) }
+
+// Prog.Flag
+type ProgFlag uint32
+
+const (
+	PF_X        ProgFlag = 0x1        /* Executable. */
+	PF_W        ProgFlag = 0x2        /* Writable. */
+	PF_R        ProgFlag = 0x4        /* Readable. */
+	PF_MASKOS   ProgFlag = 0x0ff00000 /* Operating system-specific. */
+	PF_MASKPROC ProgFlag = 0xf0000000 /* Processor-specific. */
+)
+
+var pfStrings = []intName{
+	{0x1, "PF_X"},
+	{0x2, "PF_W"},
+	{0x4, "PF_R"},
+}
+
+func (i ProgFlag) String() string   { return flagName(uint32(i), pfStrings, false) }
+func (i ProgFlag) GoString() string { return flagName(uint32(i), pfStrings, true) }
+
+// Dyn.Tag
+type DynTag int
+
+const (
+	DT_NULL         DynTag = 0  /* Terminating entry. */
+	DT_NEEDED       DynTag = 1  /* String table offset of a needed shared library. */
+	DT_PLTRELSZ     DynTag = 2  /* Total size in bytes of PLT relocations. */
+	DT_PLTGOT       DynTag = 3  /* Processor-dependent address. */
+	DT_HASH         DynTag = 4  /* Address of symbol hash table. */
+	DT_STRTAB       DynTag = 5  /* Address of string table. */
+	DT_SYMTAB       DynTag = 6  /* Address of symbol table. */
+	DT_RELA         DynTag = 7  /* Address of ElfNN_Rela relocations. */
+	DT_RELASZ       DynTag = 8  /* Total size of ElfNN_Rela relocations. */
+	DT_RELAENT      DynTag = 9  /* Size of each ElfNN_Rela relocation entry. */
+	DT_STRSZ        DynTag = 10 /* Size of string table. */
+	DT_SYMENT       DynTag = 11 /* Size of each symbol table entry. */
+	DT_INIT         DynTag = 12 /* Address of initialization function. */
+	DT_FINI         DynTag = 13 /* Address of finalization function. */
+	DT_SONAME       DynTag = 14 /* String table offset of shared object name. */
+	DT_RPATH        DynTag = 15 /* String table offset of library path. [sup] */
+	DT_SYMBOLIC     DynTag = 16 /* Indicates "symbolic" linking. [sup] */
+	DT_REL          DynTag = 17 /* Address of ElfNN_Rel relocations. */
+	DT_RELSZ        DynTag = 18 /* Total size of ElfNN_Rel relocations. */
+	DT_RELENT       DynTag = 19 /* Size of each ElfNN_Rel relocation. */
+	DT_PLTREL       DynTag = 20 /* Type of relocation used for PLT. */
+	DT_DEBUG        DynTag = 21 /* Reserved (not used). */
+	DT_TEXTREL      DynTag = 22 /* Indicates there may be relocations in non-writable segments. [sup] */
+	DT_JMPREL       DynTag = 23 /* Address of PLT relocations. */
+	DT_BIND_NOW     DynTag = 24 /* [sup] */
+	DT_INIT_ARRAY   DynTag = 25 /* Address of the array of pointers to initialization functions */
+	DT_FINI_ARRAY   DynTag = 26 /* Address of the array of pointers to termination functions */
+	DT_INIT_ARRAYSZ DynTag = 27 /* Size in bytes of the array of initialization functions. */
+	DT_FINI_ARRAYSZ DynTag = 28 /* Size in bytes of the array of terminationfunctions. */
+	DT_RUNPATH      DynTag = 29 /* String table offset of a null-terminated library search path string. */
+	DT_FLAGS        DynTag = 30 /* Object specific flag values. */
+	DT_ENCODING     DynTag = 32 /* Values greater than or equal to DT_ENCODING
+	   and less than DT_LOOS follow the rules for
+	   the interpretation of the d_un union
+	   as follows: even == 'd_ptr', even == 'd_val'
+	   or none */
+	DT_PREINIT_ARRAY   DynTag = 32         /* Address of the array of pointers to pre-initialization functions. */
+	DT_PREINIT_ARRAYSZ DynTag = 33         /* Size in bytes of the array of pre-initialization functions. */
+	DT_LOOS            DynTag = 0x6000000d /* First OS-specific */
+	DT_HIOS            DynTag = 0x6ffff000 /* Last OS-specific */
+	DT_LOPROC          DynTag = 0x70000000 /* First processor-specific type. */
+	DT_HIPROC          DynTag = 0x7fffffff /* Last processor-specific type. */
+)
+
+var dtStrings = []intName{
+	{0, "DT_NULL"},
+	{1, "DT_NEEDED"},
+	{2, "DT_PLTRELSZ"},
+	{3, "DT_PLTGOT"},
+	{4, "DT_HASH"},
+	{5, "DT_STRTAB"},
+	{6, "DT_SYMTAB"},
+	{7, "DT_RELA"},
+	{8, "DT_RELASZ"},
+	{9, "DT_RELAENT"},
+	{10, "DT_STRSZ"},
+	{11, "DT_SYMENT"},
+	{12, "DT_INIT"},
+	{13, "DT_FINI"},
+	{14, "DT_SONAME"},
+	{15, "DT_RPATH"},
+	{16, "DT_SYMBOLIC"},
+	{17, "DT_REL"},
+	{18, "DT_RELSZ"},
+	{19, "DT_RELENT"},
+	{20, "DT_PLTREL"},
+	{21, "DT_DEBUG"},
+	{22, "DT_TEXTREL"},
+	{23, "DT_JMPREL"},
+	{24, "DT_BIND_NOW"},
+	{25, "DT_INIT_ARRAY"},
+	{26, "DT_FINI_ARRAY"},
+	{27, "DT_INIT_ARRAYSZ"},
+	{28, "DT_FINI_ARRAYSZ"},
+	{29, "DT_RUNPATH"},
+	{30, "DT_FLAGS"},
+	{32, "DT_ENCODING"},
+	{32, "DT_PREINIT_ARRAY"},
+	{33, "DT_PREINIT_ARRAYSZ"},
+	{0x6000000d, "DT_LOOS"},
+	{0x6ffff000, "DT_HIOS"},
+	{0x70000000, "DT_LOPROC"},
+	{0x7fffffff, "DT_HIPROC"},
+}
+
+func (i DynTag) String() string   { return stringName(uint32(i), dtStrings, false) }
+func (i DynTag) GoString() string { return stringName(uint32(i), dtStrings, true) }
+
+// DT_FLAGS values.
+type DynFlag int
+
+const (
+	DF_ORIGIN DynFlag = 0x0001 /* Indicates that the object being loaded may
+	   make reference to the
+	   $ORIGIN substitution string */
+	DF_SYMBOLIC DynFlag = 0x0002 /* Indicates "symbolic" linking. */
+	DF_TEXTREL  DynFlag = 0x0004 /* Indicates there may be relocations in non-writable segments. */
+	DF_BIND_NOW DynFlag = 0x0008 /* Indicates that the dynamic linker should
+	   process all relocations for the object
+	   containing this entry before transferring
+	   control to the program. */
+	DF_STATIC_TLS DynFlag = 0x0010 /* Indicates that the shared object or
+	   executable contains code using a static
+	   thread-local storage scheme. */
+)
+
+var dflagStrings = []intName{
+	{0x0001, "DF_ORIGIN"},
+	{0x0002, "DF_SYMBOLIC"},
+	{0x0004, "DF_TEXTREL"},
+	{0x0008, "DF_BIND_NOW"},
+	{0x0010, "DF_STATIC_TLS"},
+}
+
+func (i DynFlag) String() string   { return flagName(uint32(i), dflagStrings, false) }
+func (i DynFlag) GoString() string { return flagName(uint32(i), dflagStrings, true) }
+
+// NType values; used in core files.
+type NType int
+
+const (
+	NT_PRSTATUS NType = 1 /* Process status. */
+	NT_FPREGSET NType = 2 /* Floating point registers. */
+	NT_PRPSINFO NType = 3 /* Process state info. */
+)
+
+var ntypeStrings = []intName{
+	{1, "NT_PRSTATUS"},
+	{2, "NT_FPREGSET"},
+	{3, "NT_PRPSINFO"},
+}
+
+func (i NType) String() string   { return stringName(uint32(i), ntypeStrings, false) }
+func (i NType) GoString() string { return stringName(uint32(i), ntypeStrings, true) }
+
+/* Symbol Binding - ELFNN_ST_BIND - st_info */
+type SymBind int
+
+const (
+	STB_LOCAL  SymBind = 0  /* Local symbol */
+	STB_GLOBAL SymBind = 1  /* Global symbol */
+	STB_WEAK   SymBind = 2  /* like global - lower precedence */
+	STB_LOOS   SymBind = 10 /* Reserved range for operating system */
+	STB_HIOS   SymBind = 12 /*   specific semantics. */
+	STB_LOPROC SymBind = 13 /* reserved range for processor */
+	STB_HIPROC SymBind = 15 /*   specific semantics. */
+)
+
+var stbStrings = []intName{
+	{0, "STB_LOCAL"},
+	{1, "STB_GLOBAL"},
+	{2, "STB_WEAK"},
+	{10, "STB_LOOS"},
+	{12, "STB_HIOS"},
+	{13, "STB_LOPROC"},
+	{15, "STB_HIPROC"},
+}
+
+func (i SymBind) String() string   { return stringName(uint32(i), stbStrings, false) }
+func (i SymBind) GoString() string { return stringName(uint32(i), stbStrings, true) }
+
+/* Symbol type - ELFNN_ST_TYPE - st_info */
+type SymType int
+
+const (
+	STT_NOTYPE  SymType = 0  /* Unspecified type. */
+	STT_OBJECT  SymType = 1  /* Data object. */
+	STT_FUNC    SymType = 2  /* Function. */
+	STT_SECTION SymType = 3  /* Section. */
+	STT_FILE    SymType = 4  /* Source file. */
+	STT_COMMON  SymType = 5  /* Uninitialized common block. */
+	STT_TLS     SymType = 6  /* TLS object. */
+	STT_LOOS    SymType = 10 /* Reserved range for operating system */
+	STT_HIOS    SymType = 12 /*   specific semantics. */
+	STT_LOPROC  SymType = 13 /* reserved range for processor */
+	STT_HIPROC  SymType = 15 /*   specific semantics. */
+)
+
+var sttStrings = []intName{
+	{0, "STT_NOTYPE"},
+	{1, "STT_OBJECT"},
+	{2, "STT_FUNC"},
+	{3, "STT_SECTION"},
+	{4, "STT_FILE"},
+	{5, "STT_COMMON"},
+	{6, "STT_TLS"},
+	{10, "STT_LOOS"},
+	{12, "STT_HIOS"},
+	{13, "STT_LOPROC"},
+	{15, "STT_HIPROC"},
+}
+
+func (i SymType) String() string   { return stringName(uint32(i), sttStrings, false) }
+func (i SymType) GoString() string { return stringName(uint32(i), sttStrings, true) }
+
+/* Symbol visibility - ELFNN_ST_VISIBILITY - st_other */
+type SymVis int
+
+const (
+	STV_DEFAULT   SymVis = 0x0 /* Default visibility (see binding). */
+	STV_INTERNAL  SymVis = 0x1 /* Special meaning in relocatable objects. */
+	STV_HIDDEN    SymVis = 0x2 /* Not visible. */
+	STV_PROTECTED SymVis = 0x3 /* Visible but not preemptible. */
+)
+
+var stvStrings = []intName{
+	{0x0, "STV_DEFAULT"},
+	{0x1, "STV_INTERNAL"},
+	{0x2, "STV_HIDDEN"},
+	{0x3, "STV_PROTECTED"},
+}
+
+func (i SymVis) String() string   { return stringName(uint32(i), stvStrings, false) }
+func (i SymVis) GoString() string { return stringName(uint32(i), stvStrings, true) }
+
+/*
+ * Relocation types.
+ */
+
+// Relocation types for x86-64.
+type R_X86_64 int
+
+const (
+	R_X86_64_NONE     R_X86_64 = 0  /* No relocation. */
+	R_X86_64_64       R_X86_64 = 1  /* Add 64 bit symbol value. */
+	R_X86_64_PC32     R_X86_64 = 2  /* PC-relative 32 bit signed sym value. */
+	R_X86_64_GOT32    R_X86_64 = 3  /* PC-relative 32 bit GOT offset. */
+	R_X86_64_PLT32    R_X86_64 = 4  /* PC-relative 32 bit PLT offset. */
+	R_X86_64_COPY     R_X86_64 = 5  /* Copy data from shared object. */
+	R_X86_64_GLOB_DAT R_X86_64 = 6  /* Set GOT entry to data address. */
+	R_X86_64_JMP_SLOT R_X86_64 = 7  /* Set GOT entry to code address. */
+	R_X86_64_RELATIVE R_X86_64 = 8  /* Add load address of shared object. */
+	R_X86_64_GOTPCREL R_X86_64 = 9  /* Add 32 bit signed pcrel offset to GOT. */
+	R_X86_64_32       R_X86_64 = 10 /* Add 32 bit zero extended symbol value */
+	R_X86_64_32S      R_X86_64 = 11 /* Add 32 bit sign extended symbol value */
+	R_X86_64_16       R_X86_64 = 12 /* Add 16 bit zero extended symbol value */
+	R_X86_64_PC16     R_X86_64 = 13 /* Add 16 bit signed extended pc relative symbol value */
+	R_X86_64_8        R_X86_64 = 14 /* Add 8 bit zero extended symbol value */
+	R_X86_64_PC8      R_X86_64 = 15 /* Add 8 bit signed extended pc relative symbol value */
+	R_X86_64_DTPMOD64 R_X86_64 = 16 /* ID of module containing symbol */
+	R_X86_64_DTPOFF64 R_X86_64 = 17 /* Offset in TLS block */
+	R_X86_64_TPOFF64  R_X86_64 = 18 /* Offset in static TLS block */
+	R_X86_64_TLSGD    R_X86_64 = 19 /* PC relative offset to GD GOT entry */
+	R_X86_64_TLSLD    R_X86_64 = 20 /* PC relative offset to LD GOT entry */
+	R_X86_64_DTPOFF32 R_X86_64 = 21 /* Offset in TLS block */
+	R_X86_64_GOTTPOFF R_X86_64 = 22 /* PC relative offset to IE GOT entry */
+	R_X86_64_TPOFF32  R_X86_64 = 23 /* Offset in static TLS block */
+)
+
+var rx86_64Strings = []intName{
+	{0, "R_X86_64_NONE"},
+	{1, "R_X86_64_64"},
+	{2, "R_X86_64_PC32"},
+	{3, "R_X86_64_GOT32"},
+	{4, "R_X86_64_PLT32"},
+	{5, "R_X86_64_COPY"},
+	{6, "R_X86_64_GLOB_DAT"},
+	{7, "R_X86_64_JMP_SLOT"},
+	{8, "R_X86_64_RELATIVE"},
+	{9, "R_X86_64_GOTPCREL"},
+	{10, "R_X86_64_32"},
+	{11, "R_X86_64_32S"},
+	{12, "R_X86_64_16"},
+	{13, "R_X86_64_PC16"},
+	{14, "R_X86_64_8"},
+	{15, "R_X86_64_PC8"},
+	{16, "R_X86_64_DTPMOD64"},
+	{17, "R_X86_64_DTPOFF64"},
+	{18, "R_X86_64_TPOFF64"},
+	{19, "R_X86_64_TLSGD"},
+	{20, "R_X86_64_TLSLD"},
+	{21, "R_X86_64_DTPOFF32"},
+	{22, "R_X86_64_GOTTPOFF"},
+	{23, "R_X86_64_TPOFF32"},
+}
+
+func (i R_X86_64) String() string   { return stringName(uint32(i), rx86_64Strings, false) }
+func (i R_X86_64) GoString() string { return stringName(uint32(i), rx86_64Strings, true) }
+
+// Relocation types for Alpha.
+type R_ALPHA int
+
+const (
+	R_ALPHA_NONE           R_ALPHA = 0  /* No reloc */
+	R_ALPHA_REFLONG        R_ALPHA = 1  /* Direct 32 bit */
+	R_ALPHA_REFQUAD        R_ALPHA = 2  /* Direct 64 bit */
+	R_ALPHA_GPREL32        R_ALPHA = 3  /* GP relative 32 bit */
+	R_ALPHA_LITERAL        R_ALPHA = 4  /* GP relative 16 bit w/optimization */
+	R_ALPHA_LITUSE         R_ALPHA = 5  /* Optimization hint for LITERAL */
+	R_ALPHA_GPDISP         R_ALPHA = 6  /* Add displacement to GP */
+	R_ALPHA_BRADDR         R_ALPHA = 7  /* PC+4 relative 23 bit shifted */
+	R_ALPHA_HINT           R_ALPHA = 8  /* PC+4 relative 16 bit shifted */
+	R_ALPHA_SREL16         R_ALPHA = 9  /* PC relative 16 bit */
+	R_ALPHA_SREL32         R_ALPHA = 10 /* PC relative 32 bit */
+	R_ALPHA_SREL64         R_ALPHA = 11 /* PC relative 64 bit */
+	R_ALPHA_OP_PUSH        R_ALPHA = 12 /* OP stack push */
+	R_ALPHA_OP_STORE       R_ALPHA = 13 /* OP stack pop and store */
+	R_ALPHA_OP_PSUB        R_ALPHA = 14 /* OP stack subtract */
+	R_ALPHA_OP_PRSHIFT     R_ALPHA = 15 /* OP stack right shift */
+	R_ALPHA_GPVALUE        R_ALPHA = 16
+	R_ALPHA_GPRELHIGH      R_ALPHA = 17
+	R_ALPHA_GPRELLOW       R_ALPHA = 18
+	R_ALPHA_IMMED_GP_16    R_ALPHA = 19
+	R_ALPHA_IMMED_GP_HI32  R_ALPHA = 20
+	R_ALPHA_IMMED_SCN_HI32 R_ALPHA = 21
+	R_ALPHA_IMMED_BR_HI32  R_ALPHA = 22
+	R_ALPHA_IMMED_LO32     R_ALPHA = 23
+	R_ALPHA_COPY           R_ALPHA = 24 /* Copy symbol at runtime */
+	R_ALPHA_GLOB_DAT       R_ALPHA = 25 /* Create GOT entry */
+	R_ALPHA_JMP_SLOT       R_ALPHA = 26 /* Create PLT entry */
+	R_ALPHA_RELATIVE       R_ALPHA = 27 /* Adjust by program base */
+)
+
+var ralphaStrings = []intName{
+	{0, "R_ALPHA_NONE"},
+	{1, "R_ALPHA_REFLONG"},
+	{2, "R_ALPHA_REFQUAD"},
+	{3, "R_ALPHA_GPREL32"},
+	{4, "R_ALPHA_LITERAL"},
+	{5, "R_ALPHA_LITUSE"},
+	{6, "R_ALPHA_GPDISP"},
+	{7, "R_ALPHA_BRADDR"},
+	{8, "R_ALPHA_HINT"},
+	{9, "R_ALPHA_SREL16"},
+	{10, "R_ALPHA_SREL32"},
+	{11, "R_ALPHA_SREL64"},
+	{12, "R_ALPHA_OP_PUSH"},
+	{13, "R_ALPHA_OP_STORE"},
+	{14, "R_ALPHA_OP_PSUB"},
+	{15, "R_ALPHA_OP_PRSHIFT"},
+	{16, "R_ALPHA_GPVALUE"},
+	{17, "R_ALPHA_GPRELHIGH"},
+	{18, "R_ALPHA_GPRELLOW"},
+	{19, "R_ALPHA_IMMED_GP_16"},
+	{20, "R_ALPHA_IMMED_GP_HI32"},
+	{21, "R_ALPHA_IMMED_SCN_HI32"},
+	{22, "R_ALPHA_IMMED_BR_HI32"},
+	{23, "R_ALPHA_IMMED_LO32"},
+	{24, "R_ALPHA_COPY"},
+	{25, "R_ALPHA_GLOB_DAT"},
+	{26, "R_ALPHA_JMP_SLOT"},
+	{27, "R_ALPHA_RELATIVE"},
+}
+
+func (i R_ALPHA) String() string   { return stringName(uint32(i), ralphaStrings, false) }
+func (i R_ALPHA) GoString() string { return stringName(uint32(i), ralphaStrings, true) }
+
+// Relocation types for ARM.
+type R_ARM int
+
+const (
+	R_ARM_NONE          R_ARM = 0 /* No relocation. */
+	R_ARM_PC24          R_ARM = 1
+	R_ARM_ABS32         R_ARM = 2
+	R_ARM_REL32         R_ARM = 3
+	R_ARM_PC13          R_ARM = 4
+	R_ARM_ABS16         R_ARM = 5
+	R_ARM_ABS12         R_ARM = 6
+	R_ARM_THM_ABS5      R_ARM = 7
+	R_ARM_ABS8          R_ARM = 8
+	R_ARM_SBREL32       R_ARM = 9
+	R_ARM_THM_PC22      R_ARM = 10
+	R_ARM_THM_PC8       R_ARM = 11
+	R_ARM_AMP_VCALL9    R_ARM = 12
+	R_ARM_SWI24         R_ARM = 13
+	R_ARM_THM_SWI8      R_ARM = 14
+	R_ARM_XPC25         R_ARM = 15
+	R_ARM_THM_XPC22     R_ARM = 16
+	R_ARM_COPY          R_ARM = 20 /* Copy data from shared object. */
+	R_ARM_GLOB_DAT      R_ARM = 21 /* Set GOT entry to data address. */
+	R_ARM_JUMP_SLOT     R_ARM = 22 /* Set GOT entry to code address. */
+	R_ARM_RELATIVE      R_ARM = 23 /* Add load address of shared object. */
+	R_ARM_GOTOFF        R_ARM = 24 /* Add GOT-relative symbol address. */
+	R_ARM_GOTPC         R_ARM = 25 /* Add PC-relative GOT table address. */
+	R_ARM_GOT32         R_ARM = 26 /* Add PC-relative GOT offset. */
+	R_ARM_PLT32         R_ARM = 27 /* Add PC-relative PLT offset. */
+	R_ARM_GNU_VTENTRY   R_ARM = 100
+	R_ARM_GNU_VTINHERIT R_ARM = 101
+	R_ARM_RSBREL32      R_ARM = 250
+	R_ARM_THM_RPC22     R_ARM = 251
+	R_ARM_RREL32        R_ARM = 252
+	R_ARM_RABS32        R_ARM = 253
+	R_ARM_RPC24         R_ARM = 254
+	R_ARM_RBASE         R_ARM = 255
+)
+
+var rarmStrings = []intName{
+	{0, "R_ARM_NONE"},
+	{1, "R_ARM_PC24"},
+	{2, "R_ARM_ABS32"},
+	{3, "R_ARM_REL32"},
+	{4, "R_ARM_PC13"},
+	{5, "R_ARM_ABS16"},
+	{6, "R_ARM_ABS12"},
+	{7, "R_ARM_THM_ABS5"},
+	{8, "R_ARM_ABS8"},
+	{9, "R_ARM_SBREL32"},
+	{10, "R_ARM_THM_PC22"},
+	{11, "R_ARM_THM_PC8"},
+	{12, "R_ARM_AMP_VCALL9"},
+	{13, "R_ARM_SWI24"},
+	{14, "R_ARM_THM_SWI8"},
+	{15, "R_ARM_XPC25"},
+	{16, "R_ARM_THM_XPC22"},
+	{20, "R_ARM_COPY"},
+	{21, "R_ARM_GLOB_DAT"},
+	{22, "R_ARM_JUMP_SLOT"},
+	{23, "R_ARM_RELATIVE"},
+	{24, "R_ARM_GOTOFF"},
+	{25, "R_ARM_GOTPC"},
+	{26, "R_ARM_GOT32"},
+	{27, "R_ARM_PLT32"},
+	{100, "R_ARM_GNU_VTENTRY"},
+	{101, "R_ARM_GNU_VTINHERIT"},
+	{250, "R_ARM_RSBREL32"},
+	{251, "R_ARM_THM_RPC22"},
+	{252, "R_ARM_RREL32"},
+	{253, "R_ARM_RABS32"},
+	{254, "R_ARM_RPC24"},
+	{255, "R_ARM_RBASE"},
+}
+
+func (i R_ARM) String() string   { return stringName(uint32(i), rarmStrings, false) }
+func (i R_ARM) GoString() string { return stringName(uint32(i), rarmStrings, true) }
+
+// Relocation types for 386.
+type R_386 int
+
+const (
+	R_386_NONE         R_386 = 0  /* No relocation. */
+	R_386_32           R_386 = 1  /* Add symbol value. */
+	R_386_PC32         R_386 = 2  /* Add PC-relative symbol value. */
+	R_386_GOT32        R_386 = 3  /* Add PC-relative GOT offset. */
+	R_386_PLT32        R_386 = 4  /* Add PC-relative PLT offset. */
+	R_386_COPY         R_386 = 5  /* Copy data from shared object. */
+	R_386_GLOB_DAT     R_386 = 6  /* Set GOT entry to data address. */
+	R_386_JMP_SLOT     R_386 = 7  /* Set GOT entry to code address. */
+	R_386_RELATIVE     R_386 = 8  /* Add load address of shared object. */
+	R_386_GOTOFF       R_386 = 9  /* Add GOT-relative symbol address. */
+	R_386_GOTPC        R_386 = 10 /* Add PC-relative GOT table address. */
+	R_386_TLS_TPOFF    R_386 = 14 /* Negative offset in static TLS block */
+	R_386_TLS_IE       R_386 = 15 /* Absolute address of GOT for -ve static TLS */
+	R_386_TLS_GOTIE    R_386 = 16 /* GOT entry for negative static TLS block */
+	R_386_TLS_LE       R_386 = 17 /* Negative offset relative to static TLS */
+	R_386_TLS_GD       R_386 = 18 /* 32 bit offset to GOT (index,off) pair */
+	R_386_TLS_LDM      R_386 = 19 /* 32 bit offset to GOT (index,zero) pair */
+	R_386_TLS_GD_32    R_386 = 24 /* 32 bit offset to GOT (index,off) pair */
+	R_386_TLS_GD_PUSH  R_386 = 25 /* pushl instruction for Sun ABI GD sequence */
+	R_386_TLS_GD_CALL  R_386 = 26 /* call instruction for Sun ABI GD sequence */
+	R_386_TLS_GD_POP   R_386 = 27 /* popl instruction for Sun ABI GD sequence */
+	R_386_TLS_LDM_32   R_386 = 28 /* 32 bit offset to GOT (index,zero) pair */
+	R_386_TLS_LDM_PUSH R_386 = 29 /* pushl instruction for Sun ABI LD sequence */
+	R_386_TLS_LDM_CALL R_386 = 30 /* call instruction for Sun ABI LD sequence */
+	R_386_TLS_LDM_POP  R_386 = 31 /* popl instruction for Sun ABI LD sequence */
+	R_386_TLS_LDO_32   R_386 = 32 /* 32 bit offset from start of TLS block */
+	R_386_TLS_IE_32    R_386 = 33 /* 32 bit offset to GOT static TLS offset entry */
+	R_386_TLS_LE_32    R_386 = 34 /* 32 bit offset within static TLS block */
+	R_386_TLS_DTPMOD32 R_386 = 35 /* GOT entry containing TLS index */
+	R_386_TLS_DTPOFF32 R_386 = 36 /* GOT entry containing TLS offset */
+	R_386_TLS_TPOFF32  R_386 = 37 /* GOT entry of -ve static TLS offset */
+)
+
+var r386Strings = []intName{
+	{0, "R_386_NONE"},
+	{1, "R_386_32"},
+	{2, "R_386_PC32"},
+	{3, "R_386_GOT32"},
+	{4, "R_386_PLT32"},
+	{5, "R_386_COPY"},
+	{6, "R_386_GLOB_DAT"},
+	{7, "R_386_JMP_SLOT"},
+	{8, "R_386_RELATIVE"},
+	{9, "R_386_GOTOFF"},
+	{10, "R_386_GOTPC"},
+	{14, "R_386_TLS_TPOFF"},
+	{15, "R_386_TLS_IE"},
+	{16, "R_386_TLS_GOTIE"},
+	{17, "R_386_TLS_LE"},
+	{18, "R_386_TLS_GD"},
+	{19, "R_386_TLS_LDM"},
+	{24, "R_386_TLS_GD_32"},
+	{25, "R_386_TLS_GD_PUSH"},
+	{26, "R_386_TLS_GD_CALL"},
+	{27, "R_386_TLS_GD_POP"},
+	{28, "R_386_TLS_LDM_32"},
+	{29, "R_386_TLS_LDM_PUSH"},
+	{30, "R_386_TLS_LDM_CALL"},
+	{31, "R_386_TLS_LDM_POP"},
+	{32, "R_386_TLS_LDO_32"},
+	{33, "R_386_TLS_IE_32"},
+	{34, "R_386_TLS_LE_32"},
+	{35, "R_386_TLS_DTPMOD32"},
+	{36, "R_386_TLS_DTPOFF32"},
+	{37, "R_386_TLS_TPOFF32"},
+}
+
+func (i R_386) String() string   { return stringName(uint32(i), r386Strings, false) }
+func (i R_386) GoString() string { return stringName(uint32(i), r386Strings, true) }
+
+// Relocation types for PowerPC.
+type R_PPC int
+
+const (
+	R_PPC_NONE            R_PPC = 0 /* No relocation. */
+	R_PPC_ADDR32          R_PPC = 1
+	R_PPC_ADDR24          R_PPC = 2
+	R_PPC_ADDR16          R_PPC = 3
+	R_PPC_ADDR16_LO       R_PPC = 4
+	R_PPC_ADDR16_HI       R_PPC = 5
+	R_PPC_ADDR16_HA       R_PPC = 6
+	R_PPC_ADDR14          R_PPC = 7
+	R_PPC_ADDR14_BRTAKEN  R_PPC = 8
+	R_PPC_ADDR14_BRNTAKEN R_PPC = 9
+	R_PPC_REL24           R_PPC = 10
+	R_PPC_REL14           R_PPC = 11
+	R_PPC_REL14_BRTAKEN   R_PPC = 12
+	R_PPC_REL14_BRNTAKEN  R_PPC = 13
+	R_PPC_GOT16           R_PPC = 14
+	R_PPC_GOT16_LO        R_PPC = 15
+	R_PPC_GOT16_HI        R_PPC = 16
+	R_PPC_GOT16_HA        R_PPC = 17
+	R_PPC_PLTREL24        R_PPC = 18
+	R_PPC_COPY            R_PPC = 19
+	R_PPC_GLOB_DAT        R_PPC = 20
+	R_PPC_JMP_SLOT        R_PPC = 21
+	R_PPC_RELATIVE        R_PPC = 22
+	R_PPC_LOCAL24PC       R_PPC = 23
+	R_PPC_UADDR32         R_PPC = 24
+	R_PPC_UADDR16         R_PPC = 25
+	R_PPC_REL32           R_PPC = 26
+	R_PPC_PLT32           R_PPC = 27
+	R_PPC_PLTREL32        R_PPC = 28
+	R_PPC_PLT16_LO        R_PPC = 29
+	R_PPC_PLT16_HI        R_PPC = 30
+	R_PPC_PLT16_HA        R_PPC = 31
+	R_PPC_SDAREL16        R_PPC = 32
+	R_PPC_SECTOFF         R_PPC = 33
+	R_PPC_SECTOFF_LO      R_PPC = 34
+	R_PPC_SECTOFF_HI      R_PPC = 35
+	R_PPC_SECTOFF_HA      R_PPC = 36
+	R_PPC_TLS             R_PPC = 67
+	R_PPC_DTPMOD32        R_PPC = 68
+	R_PPC_TPREL16         R_PPC = 69
+	R_PPC_TPREL16_LO      R_PPC = 70
+	R_PPC_TPREL16_HI      R_PPC = 71
+	R_PPC_TPREL16_HA      R_PPC = 72
+	R_PPC_TPREL32         R_PPC = 73
+	R_PPC_DTPREL16        R_PPC = 74
+	R_PPC_DTPREL16_LO     R_PPC = 75
+	R_PPC_DTPREL16_HI     R_PPC = 76
+	R_PPC_DTPREL16_HA     R_PPC = 77
+	R_PPC_DTPREL32        R_PPC = 78
+	R_PPC_GOT_TLSGD16     R_PPC = 79
+	R_PPC_GOT_TLSGD16_LO  R_PPC = 80
+	R_PPC_GOT_TLSGD16_HI  R_PPC = 81
+	R_PPC_GOT_TLSGD16_HA  R_PPC = 82
+	R_PPC_GOT_TLSLD16     R_PPC = 83
+	R_PPC_GOT_TLSLD16_LO  R_PPC = 84
+	R_PPC_GOT_TLSLD16_HI  R_PPC = 85
+	R_PPC_GOT_TLSLD16_HA  R_PPC = 86
+	R_PPC_GOT_TPREL16     R_PPC = 87
+	R_PPC_GOT_TPREL16_LO  R_PPC = 88
+	R_PPC_GOT_TPREL16_HI  R_PPC = 89
+	R_PPC_GOT_TPREL16_HA  R_PPC = 90
+	R_PPC_EMB_NADDR32     R_PPC = 101
+	R_PPC_EMB_NADDR16     R_PPC = 102
+	R_PPC_EMB_NADDR16_LO  R_PPC = 103
+	R_PPC_EMB_NADDR16_HI  R_PPC = 104
+	R_PPC_EMB_NADDR16_HA  R_PPC = 105
+	R_PPC_EMB_SDAI16      R_PPC = 106
+	R_PPC_EMB_SDA2I16     R_PPC = 107
+	R_PPC_EMB_SDA2REL     R_PPC = 108
+	R_PPC_EMB_SDA21       R_PPC = 109
+	R_PPC_EMB_MRKREF      R_PPC = 110
+	R_PPC_EMB_RELSEC16    R_PPC = 111
+	R_PPC_EMB_RELST_LO    R_PPC = 112
+	R_PPC_EMB_RELST_HI    R_PPC = 113
+	R_PPC_EMB_RELST_HA    R_PPC = 114
+	R_PPC_EMB_BIT_FLD     R_PPC = 115
+	R_PPC_EMB_RELSDA      R_PPC = 116
+)
+
+var rppcStrings = []intName{
+	{0, "R_PPC_NONE"},
+	{1, "R_PPC_ADDR32"},
+	{2, "R_PPC_ADDR24"},
+	{3, "R_PPC_ADDR16"},
+	{4, "R_PPC_ADDR16_LO"},
+	{5, "R_PPC_ADDR16_HI"},
+	{6, "R_PPC_ADDR16_HA"},
+	{7, "R_PPC_ADDR14"},
+	{8, "R_PPC_ADDR14_BRTAKEN"},
+	{9, "R_PPC_ADDR14_BRNTAKEN"},
+	{10, "R_PPC_REL24"},
+	{11, "R_PPC_REL14"},
+	{12, "R_PPC_REL14_BRTAKEN"},
+	{13, "R_PPC_REL14_BRNTAKEN"},
+	{14, "R_PPC_GOT16"},
+	{15, "R_PPC_GOT16_LO"},
+	{16, "R_PPC_GOT16_HI"},
+	{17, "R_PPC_GOT16_HA"},
+	{18, "R_PPC_PLTREL24"},
+	{19, "R_PPC_COPY"},
+	{20, "R_PPC_GLOB_DAT"},
+	{21, "R_PPC_JMP_SLOT"},
+	{22, "R_PPC_RELATIVE"},
+	{23, "R_PPC_LOCAL24PC"},
+	{24, "R_PPC_UADDR32"},
+	{25, "R_PPC_UADDR16"},
+	{26, "R_PPC_REL32"},
+	{27, "R_PPC_PLT32"},
+	{28, "R_PPC_PLTREL32"},
+	{29, "R_PPC_PLT16_LO"},
+	{30, "R_PPC_PLT16_HI"},
+	{31, "R_PPC_PLT16_HA"},
+	{32, "R_PPC_SDAREL16"},
+	{33, "R_PPC_SECTOFF"},
+	{34, "R_PPC_SECTOFF_LO"},
+	{35, "R_PPC_SECTOFF_HI"},
+	{36, "R_PPC_SECTOFF_HA"},
+
+	{67, "R_PPC_TLS"},
+	{68, "R_PPC_DTPMOD32"},
+	{69, "R_PPC_TPREL16"},
+	{70, "R_PPC_TPREL16_LO"},
+	{71, "R_PPC_TPREL16_HI"},
+	{72, "R_PPC_TPREL16_HA"},
+	{73, "R_PPC_TPREL32"},
+	{74, "R_PPC_DTPREL16"},
+	{75, "R_PPC_DTPREL16_LO"},
+	{76, "R_PPC_DTPREL16_HI"},
+	{77, "R_PPC_DTPREL16_HA"},
+	{78, "R_PPC_DTPREL32"},
+	{79, "R_PPC_GOT_TLSGD16"},
+	{80, "R_PPC_GOT_TLSGD16_LO"},
+	{81, "R_PPC_GOT_TLSGD16_HI"},
+	{82, "R_PPC_GOT_TLSGD16_HA"},
+	{83, "R_PPC_GOT_TLSLD16"},
+	{84, "R_PPC_GOT_TLSLD16_LO"},
+	{85, "R_PPC_GOT_TLSLD16_HI"},
+	{86, "R_PPC_GOT_TLSLD16_HA"},
+	{87, "R_PPC_GOT_TPREL16"},
+	{88, "R_PPC_GOT_TPREL16_LO"},
+	{89, "R_PPC_GOT_TPREL16_HI"},
+	{90, "R_PPC_GOT_TPREL16_HA"},
+
+	{101, "R_PPC_EMB_NADDR32"},
+	{102, "R_PPC_EMB_NADDR16"},
+	{103, "R_PPC_EMB_NADDR16_LO"},
+	{104, "R_PPC_EMB_NADDR16_HI"},
+	{105, "R_PPC_EMB_NADDR16_HA"},
+	{106, "R_PPC_EMB_SDAI16"},
+	{107, "R_PPC_EMB_SDA2I16"},
+	{108, "R_PPC_EMB_SDA2REL"},
+	{109, "R_PPC_EMB_SDA21"},
+	{110, "R_PPC_EMB_MRKREF"},
+	{111, "R_PPC_EMB_RELSEC16"},
+	{112, "R_PPC_EMB_RELST_LO"},
+	{113, "R_PPC_EMB_RELST_HI"},
+	{114, "R_PPC_EMB_RELST_HA"},
+	{115, "R_PPC_EMB_BIT_FLD"},
+	{116, "R_PPC_EMB_RELSDA"},
+}
+
+func (i R_PPC) String() string   { return stringName(uint32(i), rppcStrings, false) }
+func (i R_PPC) GoString() string { return stringName(uint32(i), rppcStrings, true) }
+
+// Relocation types for SPARC.
+type R_SPARC int
+
+const (
+	R_SPARC_NONE     R_SPARC = 0
+	R_SPARC_8        R_SPARC = 1
+	R_SPARC_16       R_SPARC = 2
+	R_SPARC_32       R_SPARC = 3
+	R_SPARC_DISP8    R_SPARC = 4
+	R_SPARC_DISP16   R_SPARC = 5
+	R_SPARC_DISP32   R_SPARC = 6
+	R_SPARC_WDISP30  R_SPARC = 7
+	R_SPARC_WDISP22  R_SPARC = 8
+	R_SPARC_HI22     R_SPARC = 9
+	R_SPARC_22       R_SPARC = 10
+	R_SPARC_13       R_SPARC = 11
+	R_SPARC_LO10     R_SPARC = 12
+	R_SPARC_GOT10    R_SPARC = 13
+	R_SPARC_GOT13    R_SPARC = 14
+	R_SPARC_GOT22    R_SPARC = 15
+	R_SPARC_PC10     R_SPARC = 16
+	R_SPARC_PC22     R_SPARC = 17
+	R_SPARC_WPLT30   R_SPARC = 18
+	R_SPARC_COPY     R_SPARC = 19
+	R_SPARC_GLOB_DAT R_SPARC = 20
+	R_SPARC_JMP_SLOT R_SPARC = 21
+	R_SPARC_RELATIVE R_SPARC = 22
+	R_SPARC_UA32     R_SPARC = 23
+	R_SPARC_PLT32    R_SPARC = 24
+	R_SPARC_HIPLT22  R_SPARC = 25
+	R_SPARC_LOPLT10  R_SPARC = 26
+	R_SPARC_PCPLT32  R_SPARC = 27
+	R_SPARC_PCPLT22  R_SPARC = 28
+	R_SPARC_PCPLT10  R_SPARC = 29
+	R_SPARC_10       R_SPARC = 30
+	R_SPARC_11       R_SPARC = 31
+	R_SPARC_64       R_SPARC = 32
+	R_SPARC_OLO10    R_SPARC = 33
+	R_SPARC_HH22     R_SPARC = 34
+	R_SPARC_HM10     R_SPARC = 35
+	R_SPARC_LM22     R_SPARC = 36
+	R_SPARC_PC_HH22  R_SPARC = 37
+	R_SPARC_PC_HM10  R_SPARC = 38
+	R_SPARC_PC_LM22  R_SPARC = 39
+	R_SPARC_WDISP16  R_SPARC = 40
+	R_SPARC_WDISP19  R_SPARC = 41
+	R_SPARC_GLOB_JMP R_SPARC = 42
+	R_SPARC_7        R_SPARC = 43
+	R_SPARC_5        R_SPARC = 44
+	R_SPARC_6        R_SPARC = 45
+	R_SPARC_DISP64   R_SPARC = 46
+	R_SPARC_PLT64    R_SPARC = 47
+	R_SPARC_HIX22    R_SPARC = 48
+	R_SPARC_LOX10    R_SPARC = 49
+	R_SPARC_H44      R_SPARC = 50
+	R_SPARC_M44      R_SPARC = 51
+	R_SPARC_L44      R_SPARC = 52
+	R_SPARC_REGISTER R_SPARC = 53
+	R_SPARC_UA64     R_SPARC = 54
+	R_SPARC_UA16     R_SPARC = 55
+)
+
+var rsparcStrings = []intName{
+	{0, "R_SPARC_NONE"},
+	{1, "R_SPARC_8"},
+	{2, "R_SPARC_16"},
+	{3, "R_SPARC_32"},
+	{4, "R_SPARC_DISP8"},
+	{5, "R_SPARC_DISP16"},
+	{6, "R_SPARC_DISP32"},
+	{7, "R_SPARC_WDISP30"},
+	{8, "R_SPARC_WDISP22"},
+	{9, "R_SPARC_HI22"},
+	{10, "R_SPARC_22"},
+	{11, "R_SPARC_13"},
+	{12, "R_SPARC_LO10"},
+	{13, "R_SPARC_GOT10"},
+	{14, "R_SPARC_GOT13"},
+	{15, "R_SPARC_GOT22"},
+	{16, "R_SPARC_PC10"},
+	{17, "R_SPARC_PC22"},
+	{18, "R_SPARC_WPLT30"},
+	{19, "R_SPARC_COPY"},
+	{20, "R_SPARC_GLOB_DAT"},
+	{21, "R_SPARC_JMP_SLOT"},
+	{22, "R_SPARC_RELATIVE"},
+	{23, "R_SPARC_UA32"},
+	{24, "R_SPARC_PLT32"},
+	{25, "R_SPARC_HIPLT22"},
+	{26, "R_SPARC_LOPLT10"},
+	{27, "R_SPARC_PCPLT32"},
+	{28, "R_SPARC_PCPLT22"},
+	{29, "R_SPARC_PCPLT10"},
+	{30, "R_SPARC_10"},
+	{31, "R_SPARC_11"},
+	{32, "R_SPARC_64"},
+	{33, "R_SPARC_OLO10"},
+	{34, "R_SPARC_HH22"},
+	{35, "R_SPARC_HM10"},
+	{36, "R_SPARC_LM22"},
+	{37, "R_SPARC_PC_HH22"},
+	{38, "R_SPARC_PC_HM10"},
+	{39, "R_SPARC_PC_LM22"},
+	{40, "R_SPARC_WDISP16"},
+	{41, "R_SPARC_WDISP19"},
+	{42, "R_SPARC_GLOB_JMP"},
+	{43, "R_SPARC_7"},
+	{44, "R_SPARC_5"},
+	{45, "R_SPARC_6"},
+	{46, "R_SPARC_DISP64"},
+	{47, "R_SPARC_PLT64"},
+	{48, "R_SPARC_HIX22"},
+	{49, "R_SPARC_LOX10"},
+	{50, "R_SPARC_H44"},
+	{51, "R_SPARC_M44"},
+	{52, "R_SPARC_L44"},
+	{53, "R_SPARC_REGISTER"},
+	{54, "R_SPARC_UA64"},
+	{55, "R_SPARC_UA16"},
+}
+
+func (i R_SPARC) String() string   { return stringName(uint32(i), rsparcStrings, false) }
+func (i R_SPARC) GoString() string { return stringName(uint32(i), rsparcStrings, true) }
+
+// Magic number for the elf trampoline, chosen wisely to be an immediate value.
+const ARM_MAGIC_TRAMP_NUMBER = 0x5c000003
+
+
+// ELF32 File header.
+type Header32 struct {
+	Ident     [EI_NIDENT]byte /* File identification. */
+	Type      uint16          /* File type. */
+	Machine   uint16          /* Machine architecture. */
+	Version   uint32          /* ELF format version. */
+	Entry     uint32          /* Entry point. */
+	Phoff     uint32          /* Program header file offset. */
+	Shoff     uint32          /* Section header file offset. */
+	Flags     uint32          /* Architecture-specific flags. */
+	Ehsize    uint16          /* Size of ELF header in bytes. */
+	Phentsize uint16          /* Size of program header entry. */
+	Phnum     uint16          /* Number of program header entries. */
+	Shentsize uint16          /* Size of section header entry. */
+	Shnum     uint16          /* Number of section header entries. */
+	Shstrndx  uint16          /* Section name strings section. */
+}
+
+// ELF32 Section header.
+type Section32 struct {
+	Name      uint32 /* Section name (index into the section header string table). */
+	Type      uint32 /* Section type. */
+	Flags     uint32 /* Section flags. */
+	Addr      uint32 /* Address in memory image. */
+	Off       uint32 /* Offset in file. */
+	Size      uint32 /* Size in bytes. */
+	Link      uint32 /* Index of a related section. */
+	Info      uint32 /* Depends on section type. */
+	Addralign uint32 /* Alignment in bytes. */
+	Entsize   uint32 /* Size of each entry in section. */
+}
+
+// ELF32 Program header.
+type Prog32 struct {
+	Type   uint32 /* Entry type. */
+	Off    uint32 /* File offset of contents. */
+	Vaddr  uint32 /* Virtual address in memory image. */
+	Paddr  uint32 /* Physical address (not used). */
+	Filesz uint32 /* Size of contents in file. */
+	Memsz  uint32 /* Size of contents in memory. */
+	Flags  uint32 /* Access permission flags. */
+	Align  uint32 /* Alignment in memory and file. */
+}
+
+// ELF32 Dynamic structure.  The ".dynamic" section contains an array of them.
+type Dyn32 struct {
+	Tag int32  /* Entry type. */
+	Val uint32 /* Integer/Address value. */
+}
+
+/*
+ * Relocation entries.
+ */
+
+// ELF32 Relocations that don't need an addend field.
+type Rel32 struct {
+	Off  uint32 /* Location to be relocated. */
+	Info uint32 /* Relocation type and symbol index. */
+}
+
+// ELF32 Relocations that need an addend field.
+type Rela32 struct {
+	Off    uint32 /* Location to be relocated. */
+	Info   uint32 /* Relocation type and symbol index. */
+	Addend int32  /* Addend. */
+}
+
+func R_SYM32(info uint32) uint32      { return uint32(info >> 8) }
+func R_TYPE32(info uint32) uint32     { return uint32(info & 0xff) }
+func R_INFO32(sym, typ uint32) uint32 { return sym<<8 | typ }
+
+// ELF32 Symbol.
+type Sym32 struct {
+	Name  uint32
+	Value uint32
+	Size  uint32
+	Info  uint8
+	Other uint8
+	Shndx uint16
+}
+
+const Sym32Size = 16
+
+func ST_BIND(info uint8) SymBind { return SymBind(info >> 4) }
+func ST_TYPE(info uint8) SymType { return SymType(info & 0xF) }
+func ST_INFO(bind SymBind, typ SymType) uint8 {
+	return uint8(bind)<<4 | uint8(typ)&0xf
+}
+func ST_VISIBILITY(other uint8) SymVis { return SymVis(other & 3) }
+
+/*
+ * ELF64
+ */
+
+// ELF64 file header.
+type Header64 struct {
+	Ident     [EI_NIDENT]byte /* File identification. */
+	Type      uint16          /* File type. */
+	Machine   uint16          /* Machine architecture. */
+	Version   uint32          /* ELF format version. */
+	Entry     uint64          /* Entry point. */
+	Phoff     uint64          /* Program header file offset. */
+	Shoff     uint64          /* Section header file offset. */
+	Flags     uint32          /* Architecture-specific flags. */
+	Ehsize    uint16          /* Size of ELF header in bytes. */
+	Phentsize uint16          /* Size of program header entry. */
+	Phnum     uint16          /* Number of program header entries. */
+	Shentsize uint16          /* Size of section header entry. */
+	Shnum     uint16          /* Number of section header entries. */
+	Shstrndx  uint16          /* Section name strings section. */
+}
+
+// ELF64 Section header.
+type Section64 struct {
+	Name      uint32 /* Section name (index into the section header string table). */
+	Type      uint32 /* Section type. */
+	Flags     uint64 /* Section flags. */
+	Addr      uint64 /* Address in memory image. */
+	Off       uint64 /* Offset in file. */
+	Size      uint64 /* Size in bytes. */
+	Link      uint32 /* Index of a related section. */
+	Info      uint32 /* Depends on section type. */
+	Addralign uint64 /* Alignment in bytes. */
+	Entsize   uint64 /* Size of each entry in section. */
+}
+
+// ELF64 Program header.
+type Prog64 struct {
+	Type   uint32 /* Entry type. */
+	Flags  uint32 /* Access permission flags. */
+	Off    uint64 /* File offset of contents. */
+	Vaddr  uint64 /* Virtual address in memory image. */
+	Paddr  uint64 /* Physical address (not used). */
+	Filesz uint64 /* Size of contents in file. */
+	Memsz  uint64 /* Size of contents in memory. */
+	Align  uint64 /* Alignment in memory and file. */
+}
+
+// ELF64 Dynamic structure.  The ".dynamic" section contains an array of them.
+type Dyn64 struct {
+	Tag int64  /* Entry type. */
+	Val uint64 /* Integer/address value */
+}
+
+/*
+ * Relocation entries.
+ */
+
+/* ELF64 relocations that don't need an addend field. */
+type Rel64 struct {
+	Off  uint64 /* Location to be relocated. */
+	Info uint64 /* Relocation type and symbol index. */
+}
+
+/* ELF64 relocations that need an addend field. */
+type Rela64 struct {
+	Off    uint64 /* Location to be relocated. */
+	Info   uint64 /* Relocation type and symbol index. */
+	Addend int64  /* Addend. */
+}
+
+func R_SYM64(info uint64) uint32    { return uint32(info >> 32) }
+func R_TYPE64(info uint64) uint32   { return uint32(info) }
+func R_INFO(sym, typ uint32) uint64 { return uint64(sym)<<32 | uint64(typ) }
+
+
+// ELF64 symbol table entries.
+type Sym64 struct {
+	Name  uint32 /* String table index of name. */
+	Info  uint8  /* Type and binding information. */
+	Other uint8  /* Reserved (not used). */
+	Shndx uint16 /* Section index of symbol. */
+	Value uint64 /* Symbol value. */
+	Size  uint64 /* Size of associated object. */
+}
+
+const Sym64Size = 24
+
+type intName struct {
+	i uint32
+	s string
+}
+
+func stringName(i uint32, names []intName, goSyntax bool) string {
+	for _, n := range names {
+		if n.i == i {
+			if goSyntax {
+				return "elf." + n.s
+			}
+			return n.s
+		}
+	}
+
+	// second pass - look for smaller to add with.
+	// assume sorted already
+	for j := len(names) - 1; j >= 0; j-- {
+		n := names[j]
+		if n.i < i {
+			s := n.s
+			if goSyntax {
+				s = "elf." + s
+			}
+			return s + "+" + strconv.Uitoa64(uint64(i-n.i))
+		}
+	}
+
+	return strconv.Uitoa64(uint64(i))
+}
+
+func flagName(i uint32, names []intName, goSyntax bool) string {
+	s := ""
+	for _, n := range names {
+		if n.i&i == n.i {
+			if len(s) > 0 {
+				s += "+"
+			}
+			if goSyntax {
+				s += "elf."
+			}
+			s += n.s
+			i -= n.i
+		}
+	}
+	if len(s) == 0 {
+		return "0x" + strconv.Uitob64(uint64(i), 16)
+	}
+	if i != 0 {
+		s += "+0x" + strconv.Uitob64(uint64(i), 16)
+	}
+	return s
+}
diff --git a/libgo/go/debug/elf/elf_test.go b/libgo/go/debug/elf/elf_test.go
new file mode 100644
index 000000000..67b961b5c
--- /dev/null
+++ b/libgo/go/debug/elf/elf_test.go
@@ -0,0 +1,49 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package elf
+
+import (
+	"fmt"
+	"testing"
+)
+
+type nameTest struct {
+	val interface{}
+	str string
+}
+
+var nameTests = []nameTest{
+	{ELFOSABI_LINUX, "ELFOSABI_LINUX"},
+	{ET_EXEC, "ET_EXEC"},
+	{EM_860, "EM_860"},
+	{SHN_LOPROC, "SHN_LOPROC"},
+	{SHT_PROGBITS, "SHT_PROGBITS"},
+	{SHF_MERGE + SHF_TLS, "SHF_MERGE+SHF_TLS"},
+	{PT_LOAD, "PT_LOAD"},
+	{PF_W + PF_R + 0x50, "PF_W+PF_R+0x50"},
+	{DT_SYMBOLIC, "DT_SYMBOLIC"},
+	{DF_BIND_NOW, "DF_BIND_NOW"},
+	{NT_FPREGSET, "NT_FPREGSET"},
+	{STB_GLOBAL, "STB_GLOBAL"},
+	{STT_COMMON, "STT_COMMON"},
+	{STV_HIDDEN, "STV_HIDDEN"},
+	{R_X86_64_PC32, "R_X86_64_PC32"},
+	{R_ALPHA_OP_PUSH, "R_ALPHA_OP_PUSH"},
+	{R_ARM_THM_ABS5, "R_ARM_THM_ABS5"},
+	{R_386_GOT32, "R_386_GOT32"},
+	{R_PPC_GOT16_HI, "R_PPC_GOT16_HI"},
+	{R_SPARC_GOT22, "R_SPARC_GOT22"},
+	{ET_LOOS + 5, "ET_LOOS+5"},
+	{ProgFlag(0x50), "0x50"},
+}
+
+func TestNames(t *testing.T) {
+	for i, tt := range nameTests {
+		s := fmt.Sprint(tt.val)
+		if s != tt.str {
+			t.Errorf("#%d: want %q have %q", i, s, tt.str)
+		}
+	}
+}
diff --git a/libgo/go/debug/elf/file.go b/libgo/go/debug/elf/file.go
new file mode 100644
index 000000000..e69317a75
--- /dev/null
+++ b/libgo/go/debug/elf/file.go
@@ -0,0 +1,605 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package elf implements access to ELF object files.
+package elf
+
+import (
+	"bytes"
+	"debug/dwarf"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"os"
+)
+
+// TODO: error reporting detail
+
+/*
+ * Internal ELF representation
+ */
+
+// A FileHeader represents an ELF file header.
+type FileHeader struct {
+	Class      Class
+	Data       Data
+	Version    Version
+	OSABI      OSABI
+	ABIVersion uint8
+	ByteOrder  binary.ByteOrder
+	Type       Type
+	Machine    Machine
+}
+
+// A File represents an open ELF file.
+type File struct {
+	FileHeader
+	Sections []*Section
+	Progs    []*Prog
+	closer   io.Closer
+}
+
+// A SectionHeader represents a single ELF section header.
+type SectionHeader struct {
+	Name      string
+	Type      SectionType
+	Flags     SectionFlag
+	Addr      uint64
+	Offset    uint64
+	Size      uint64
+	Link      uint32
+	Info      uint32
+	Addralign uint64
+	Entsize   uint64
+}
+
+// A Section represents a single section in an ELF file.
+type Section struct {
+	SectionHeader
+
+	// Embed ReaderAt for ReadAt method.
+	// Do not embed SectionReader directly
+	// to avoid having Read and Seek.
+	// If a client wants Read and Seek it must use
+	// Open() to avoid fighting over the seek offset
+	// with other clients.
+	io.ReaderAt
+	sr *io.SectionReader
+}
+
+// Data reads and returns the contents of the ELF section.
+func (s *Section) Data() ([]byte, os.Error) {
+	dat := make([]byte, s.sr.Size())
+	n, err := s.sr.ReadAt(dat, 0)
+	return dat[0:n], err
+}
+
+// stringTable reads and returns the string table given by the
+// specified link value.
+func (f *File) stringTable(link uint32) ([]byte, os.Error) {
+	if link <= 0 || link >= uint32(len(f.Sections)) {
+		return nil, os.ErrorString("section has invalid string table link")
+	}
+	return f.Sections[link].Data()
+}
+
+// Open returns a new ReadSeeker reading the ELF section.
+func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) }
+
+// A ProgHeader represents a single ELF program header.
+type ProgHeader struct {
+	Type   ProgType
+	Flags  ProgFlag
+	Vaddr  uint64
+	Paddr  uint64
+	Filesz uint64
+	Memsz  uint64
+	Align  uint64
+}
+
+// A Prog represents a single ELF program header in an ELF binary.
+type Prog struct {
+	ProgHeader
+
+	// Embed ReaderAt for ReadAt method.
+	// Do not embed SectionReader directly
+	// to avoid having Read and Seek.
+	// If a client wants Read and Seek it must use
+	// Open() to avoid fighting over the seek offset
+	// with other clients.
+	io.ReaderAt
+	sr *io.SectionReader
+}
+
+// Open returns a new ReadSeeker reading the ELF program body.
+func (p *Prog) Open() io.ReadSeeker { return io.NewSectionReader(p.sr, 0, 1<<63-1) }
+
+// A Symbol represents an entry in an ELF symbol table section.
+type Symbol struct {
+	Name        string
+	Info, Other byte
+	Section     SectionIndex
+	Value, Size uint64
+}
+
+/*
+ * ELF reader
+ */
+
+type FormatError struct {
+	off int64
+	msg string
+	val interface{}
+}
+
+func (e *FormatError) String() string {
+	msg := e.msg
+	if e.val != nil {
+		msg += fmt.Sprintf(" '%v' ", e.val)
+	}
+	msg += fmt.Sprintf("in record at byte %#x", e.off)
+	return msg
+}
+
+// Open opens the named file using os.Open and prepares it for use as an ELF binary.
+func Open(name string) (*File, os.Error) {
+	f, err := os.Open(name, os.O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+	ff, err := NewFile(f)
+	if err != nil {
+		f.Close()
+		return nil, err
+	}
+	ff.closer = f
+	return ff, nil
+}
+
+// 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
+	if f.closer != nil {
+		err = f.closer.Close()
+		f.closer = nil
+	}
+	return err
+}
+
+// SectionByType returns the first section in f with the
+// given type, or nil if there is no such section.
+func (f *File) SectionByType(typ SectionType) *Section {
+	for _, s := range f.Sections {
+		if s.Type == typ {
+			return s
+		}
+	}
+	return nil
+}
+
+// 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) {
+	sr := io.NewSectionReader(r, 0, 1<<63-1)
+	// Read and decode ELF identifier
+	var ident [16]uint8
+	if _, err := r.ReadAt(ident[0:], 0); err != nil {
+		return nil, err
+	}
+	if ident[0] != '\x7f' || ident[1] != 'E' || ident[2] != 'L' || ident[3] != 'F' {
+		return nil, &FormatError{0, "bad magic number", ident[0:4]}
+	}
+
+	f := new(File)
+	f.Class = Class(ident[EI_CLASS])
+	switch f.Class {
+	case ELFCLASS32:
+	case ELFCLASS64:
+		// ok
+	default:
+		return nil, &FormatError{0, "unknown ELF class", f.Class}
+	}
+
+	f.Data = Data(ident[EI_DATA])
+	switch f.Data {
+	case ELFDATA2LSB:
+		f.ByteOrder = binary.LittleEndian
+	case ELFDATA2MSB:
+		f.ByteOrder = binary.BigEndian
+	default:
+		return nil, &FormatError{0, "unknown ELF data encoding", f.Data}
+	}
+
+	f.Version = Version(ident[EI_VERSION])
+	if f.Version != EV_CURRENT {
+		return nil, &FormatError{0, "unknown ELF version", f.Version}
+	}
+
+	f.OSABI = OSABI(ident[EI_OSABI])
+	f.ABIVersion = ident[EI_ABIVERSION]
+
+	// Read ELF file header
+	var shoff int64
+	var shentsize, shnum, shstrndx int
+	shstrndx = -1
+	switch f.Class {
+	case ELFCLASS32:
+		hdr := new(Header32)
+		sr.Seek(0, 0)
+		if err := binary.Read(sr, f.ByteOrder, hdr); err != nil {
+			return nil, err
+		}
+		f.Type = Type(hdr.Type)
+		f.Machine = Machine(hdr.Machine)
+		if v := Version(hdr.Version); v != f.Version {
+			return nil, &FormatError{0, "mismatched ELF version", v}
+		}
+		shoff = int64(hdr.Shoff)
+		shentsize = int(hdr.Shentsize)
+		shnum = int(hdr.Shnum)
+		shstrndx = int(hdr.Shstrndx)
+	case ELFCLASS64:
+		hdr := new(Header64)
+		sr.Seek(0, 0)
+		if err := binary.Read(sr, f.ByteOrder, hdr); err != nil {
+			return nil, err
+		}
+		f.Type = Type(hdr.Type)
+		f.Machine = Machine(hdr.Machine)
+		if v := Version(hdr.Version); v != f.Version {
+			return nil, &FormatError{0, "mismatched ELF version", v}
+		}
+		shoff = int64(hdr.Shoff)
+		shentsize = int(hdr.Shentsize)
+		shnum = int(hdr.Shnum)
+		shstrndx = int(hdr.Shstrndx)
+	}
+	if shstrndx < 0 || shstrndx >= shnum {
+		return nil, &FormatError{0, "invalid ELF shstrndx", shstrndx}
+	}
+
+	// Read program headers
+	// TODO
+
+	// Read section headers
+	f.Sections = make([]*Section, shnum)
+	names := make([]uint32, shnum)
+	for i := 0; i < shnum; i++ {
+		off := shoff + int64(i)*int64(shentsize)
+		sr.Seek(off, 0)
+		s := new(Section)
+		switch f.Class {
+		case ELFCLASS32:
+			sh := new(Section32)
+			if err := binary.Read(sr, f.ByteOrder, sh); err != nil {
+				return nil, err
+			}
+			names[i] = sh.Name
+			s.SectionHeader = SectionHeader{
+				Type:      SectionType(sh.Type),
+				Flags:     SectionFlag(sh.Flags),
+				Addr:      uint64(sh.Addr),
+				Offset:    uint64(sh.Off),
+				Size:      uint64(sh.Size),
+				Link:      uint32(sh.Link),
+				Info:      uint32(sh.Info),
+				Addralign: uint64(sh.Addralign),
+				Entsize:   uint64(sh.Entsize),
+			}
+		case ELFCLASS64:
+			sh := new(Section64)
+			if err := binary.Read(sr, f.ByteOrder, sh); err != nil {
+				return nil, err
+			}
+			names[i] = sh.Name
+			s.SectionHeader = SectionHeader{
+				Type:      SectionType(sh.Type),
+				Flags:     SectionFlag(sh.Flags),
+				Offset:    uint64(sh.Off),
+				Size:      uint64(sh.Size),
+				Addr:      uint64(sh.Addr),
+				Link:      uint32(sh.Link),
+				Info:      uint32(sh.Info),
+				Addralign: uint64(sh.Addralign),
+				Entsize:   uint64(sh.Entsize),
+			}
+		}
+		s.sr = io.NewSectionReader(r, int64(s.Offset), int64(s.Size))
+		s.ReaderAt = s.sr
+		f.Sections[i] = s
+	}
+
+	// Load section header string table.
+	shstrtab, err := f.Sections[shstrndx].Data()
+	if err != nil {
+		return nil, err
+	}
+	for i, s := range f.Sections {
+		var ok bool
+		s.Name, ok = getString(shstrtab, int(names[i]))
+		if !ok {
+			return nil, &FormatError{shoff + int64(i*shentsize), "bad section name index", names[i]}
+		}
+	}
+
+	return f, nil
+}
+
+// getSymbols returns a slice of Symbols from parsing the symbol table
+// with the given type.
+func (f *File) getSymbols(typ SectionType) ([]Symbol, os.Error) {
+	switch f.Class {
+	case ELFCLASS64:
+		return f.getSymbols64(typ)
+
+	case ELFCLASS32:
+		return f.getSymbols32(typ)
+	}
+
+	return nil, os.ErrorString("not implemented")
+}
+
+func (f *File) getSymbols32(typ SectionType) ([]Symbol, os.Error) {
+	symtabSection := f.SectionByType(typ)
+	if symtabSection == nil {
+		return nil, os.ErrorString("no symbol section")
+	}
+
+	data, err := symtabSection.Data()
+	if err != nil {
+		return nil, os.ErrorString("cannot load symbol section")
+	}
+	symtab := bytes.NewBuffer(data)
+	if symtab.Len()%Sym32Size != 0 {
+		return nil, os.ErrorString("length of symbol section is not a multiple of SymSize")
+	}
+
+	strdata, err := f.stringTable(symtabSection.Link)
+	if err != nil {
+		return nil, os.ErrorString("cannot load string table section")
+	}
+
+	// The first entry is all zeros.
+	var skip [Sym32Size]byte
+	symtab.Read(skip[0:])
+
+	symbols := make([]Symbol, symtab.Len()/Sym32Size)
+
+	i := 0
+	var sym Sym32
+	for symtab.Len() > 0 {
+		binary.Read(symtab, f.ByteOrder, &sym)
+		str, _ := getString(strdata, int(sym.Name))
+		symbols[i].Name = str
+		symbols[i].Info = sym.Info
+		symbols[i].Other = sym.Other
+		symbols[i].Section = SectionIndex(sym.Shndx)
+		symbols[i].Value = uint64(sym.Value)
+		symbols[i].Size = uint64(sym.Size)
+		i++
+	}
+
+	return symbols, nil
+}
+
+func (f *File) getSymbols64(typ SectionType) ([]Symbol, os.Error) {
+	symtabSection := f.SectionByType(typ)
+	if symtabSection == nil {
+		return nil, os.ErrorString("no symbol section")
+	}
+
+	data, err := symtabSection.Data()
+	if err != nil {
+		return nil, os.ErrorString("cannot load symbol section")
+	}
+	symtab := bytes.NewBuffer(data)
+	if symtab.Len()%Sym64Size != 0 {
+		return nil, os.ErrorString("length of symbol section is not a multiple of Sym64Size")
+	}
+
+	strdata, err := f.stringTable(symtabSection.Link)
+	if err != nil {
+		return nil, os.ErrorString("cannot load string table section")
+	}
+
+	// The first entry is all zeros.
+	var skip [Sym64Size]byte
+	symtab.Read(skip[0:])
+
+	symbols := make([]Symbol, symtab.Len()/Sym64Size)
+
+	i := 0
+	var sym Sym64
+	for symtab.Len() > 0 {
+		binary.Read(symtab, f.ByteOrder, &sym)
+		str, _ := getString(strdata, int(sym.Name))
+		symbols[i].Name = str
+		symbols[i].Info = sym.Info
+		symbols[i].Other = sym.Other
+		symbols[i].Section = SectionIndex(sym.Shndx)
+		symbols[i].Value = sym.Value
+		symbols[i].Size = sym.Size
+		i++
+	}
+
+	return symbols, nil
+}
+
+// getString extracts a string from an ELF string table.
+func getString(section []byte, start int) (string, bool) {
+	if start < 0 || start >= len(section) {
+		return "", false
+	}
+
+	for end := start; end < len(section); end++ {
+		if section[end] == 0 {
+			return string(section[start:end]), true
+		}
+	}
+	return "", false
+}
+
+// Section returns a section with the given name, or nil if no such
+// section exists.
+func (f *File) Section(name string) *Section {
+	for _, s := range f.Sections {
+		if s.Name == name {
+			return s
+		}
+	}
+	return nil
+}
+
+// applyRelocations applies relocations to dst. rels is a relocations section
+// in RELA format.
+func (f *File) applyRelocations(dst []byte, rels []byte) os.Error {
+	if f.Class == ELFCLASS64 && f.Machine == EM_X86_64 {
+		return f.applyRelocationsAMD64(dst, rels)
+	}
+
+	return os.ErrorString("not implemented")
+}
+
+func (f *File) applyRelocationsAMD64(dst []byte, rels []byte) os.Error {
+	if len(rels)%Sym64Size != 0 {
+		return os.ErrorString("length of relocation section is not a multiple of Sym64Size")
+	}
+
+	symbols, err := f.getSymbols(SHT_SYMTAB)
+	if err != nil {
+		return err
+	}
+
+	b := bytes.NewBuffer(rels)
+	var rela Rela64
+
+	for b.Len() > 0 {
+		binary.Read(b, f.ByteOrder, &rela)
+		symNo := rela.Info >> 32
+		t := R_X86_64(rela.Info & 0xffff)
+
+		if symNo >= uint64(len(symbols)) {
+			continue
+		}
+		sym := &symbols[symNo]
+		if SymType(sym.Info&0xf) != STT_SECTION {
+			// We don't handle non-section relocations for now.
+			continue
+		}
+
+		switch t {
+		case R_X86_64_64:
+			if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 {
+				continue
+			}
+			f.ByteOrder.PutUint64(dst[rela.Off:rela.Off+8], uint64(rela.Addend))
+		case R_X86_64_32:
+			if rela.Off+4 >= uint64(len(dst)) || rela.Addend < 0 {
+				continue
+			}
+			f.ByteOrder.PutUint32(dst[rela.Off:rela.Off+4], uint32(rela.Addend))
+		}
+	}
+
+	return nil
+}
+
+func (f *File) DWARF() (*dwarf.Data, os.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.
+	var names = [...]string{"abbrev", "info", "str"}
+	var dat [len(names)][]byte
+	for i, name := range names {
+		name = ".debug_" + name
+		s := f.Section(name)
+		if s == nil {
+			continue
+		}
+		b, err := s.Data()
+		if err != nil && uint64(len(b)) < s.Size {
+			return nil, err
+		}
+		dat[i] = b
+	}
+
+	// If there's a relocation table for .debug_info, we have to process it
+	// now otherwise the data in .debug_info is invalid for x86-64 objects.
+	rela := f.Section(".rela.debug_info")
+	if rela != nil && rela.Type == SHT_RELA && f.Machine == EM_X86_64 {
+		data, err := rela.Data()
+		if err != nil {
+			return nil, err
+		}
+		err = f.applyRelocations(dat[1], data)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	abbrev, info, str := dat[0], dat[1], dat[2]
+	return dwarf.New(abbrev, nil, nil, info, nil, nil, nil, str)
+}
+
+// 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.
+// It does not return weak symbols.
+func (f *File) ImportedSymbols() ([]string, os.Error) {
+	sym, err := f.getSymbols(SHT_DYNSYM)
+	if err != nil {
+		return nil, err
+	}
+	var all []string
+	for _, s := range sym {
+		if ST_BIND(s.Info) == STB_GLOBAL && s.Section == SHN_UNDEF {
+			all = append(all, s.Name)
+		}
+	}
+	return all, nil
+}
+
+// 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) {
+	ds := f.SectionByType(SHT_DYNAMIC)
+	if ds == nil {
+		// not dynamic, so no libraries
+		return nil, nil
+	}
+	d, err := ds.Data()
+	if err != nil {
+		return nil, err
+	}
+	str, err := f.stringTable(ds.Link)
+	if err != nil {
+		return nil, err
+	}
+	var all []string
+	for len(d) > 0 {
+		var tag DynTag
+		var value uint64
+		switch f.Class {
+		case ELFCLASS32:
+			tag = DynTag(f.ByteOrder.Uint32(d[0:4]))
+			value = uint64(f.ByteOrder.Uint32(d[4:8]))
+			d = d[8:]
+		case ELFCLASS64:
+			tag = DynTag(f.ByteOrder.Uint64(d[0:8]))
+			value = f.ByteOrder.Uint64(d[8:16])
+			d = d[16:]
+		}
+		if tag == DT_NEEDED {
+			s, ok := getString(str, int(value))
+			if ok {
+				all = append(all, s)
+			}
+		}
+	}
+
+	return all, nil
+}
diff --git a/libgo/go/debug/elf/file_test.go b/libgo/go/debug/elf/file_test.go
new file mode 100644
index 000000000..84068ea12
--- /dev/null
+++ b/libgo/go/debug/elf/file_test.go
@@ -0,0 +1,180 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package elf
+
+import (
+	"debug/dwarf"
+	"encoding/binary"
+	"reflect"
+	"testing"
+)
+
+type fileTest struct {
+	file     string
+	hdr      FileHeader
+	sections []SectionHeader
+}
+
+var fileTests = []fileTest{
+	{
+		"testdata/gcc-386-freebsd-exec",
+		FileHeader{ELFCLASS32, ELFDATA2LSB, EV_CURRENT, ELFOSABI_FREEBSD, 0, binary.LittleEndian, ET_EXEC, EM_386},
+		[]SectionHeader{
+			{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+			{".interp", SHT_PROGBITS, SHF_ALLOC, 0x80480d4, 0xd4, 0x15, 0x0, 0x0, 0x1, 0x0},
+			{".hash", SHT_HASH, SHF_ALLOC, 0x80480ec, 0xec, 0x90, 0x3, 0x0, 0x4, 0x4},
+			{".dynsym", SHT_DYNSYM, SHF_ALLOC, 0x804817c, 0x17c, 0x110, 0x4, 0x1, 0x4, 0x10},
+			{".dynstr", SHT_STRTAB, SHF_ALLOC, 0x804828c, 0x28c, 0xbb, 0x0, 0x0, 0x1, 0x0},
+			{".rel.plt", SHT_REL, SHF_ALLOC, 0x8048348, 0x348, 0x20, 0x3, 0x7, 0x4, 0x8},
+			{".init", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x8048368, 0x368, 0x11, 0x0, 0x0, 0x4, 0x0},
+			{".plt", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x804837c, 0x37c, 0x50, 0x0, 0x0, 0x4, 0x4},
+			{".text", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x80483cc, 0x3cc, 0x180, 0x0, 0x0, 0x4, 0x0},
+			{".fini", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x804854c, 0x54c, 0xc, 0x0, 0x0, 0x4, 0x0},
+			{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x8048558, 0x558, 0xa3, 0x0, 0x0, 0x1, 0x0},
+			{".data", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80495fc, 0x5fc, 0xc, 0x0, 0x0, 0x4, 0x0},
+			{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x8049608, 0x608, 0x4, 0x0, 0x0, 0x4, 0x0},
+			{".dynamic", SHT_DYNAMIC, SHF_WRITE + SHF_ALLOC, 0x804960c, 0x60c, 0x98, 0x4, 0x0, 0x4, 0x8},
+			{".ctors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496a4, 0x6a4, 0x8, 0x0, 0x0, 0x4, 0x0},
+			{".dtors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496ac, 0x6ac, 0x8, 0x0, 0x0, 0x4, 0x0},
+			{".jcr", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496b4, 0x6b4, 0x4, 0x0, 0x0, 0x4, 0x0},
+			{".got", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496b8, 0x6b8, 0x1c, 0x0, 0x0, 0x4, 0x4},
+			{".bss", SHT_NOBITS, SHF_WRITE + SHF_ALLOC, 0x80496d4, 0x6d4, 0x20, 0x0, 0x0, 0x4, 0x0},
+			{".comment", SHT_PROGBITS, 0x0, 0x0, 0x6d4, 0x12d, 0x0, 0x0, 0x1, 0x0},
+			{".debug_aranges", SHT_PROGBITS, 0x0, 0x0, 0x801, 0x20, 0x0, 0x0, 0x1, 0x0},
+			{".debug_pubnames", SHT_PROGBITS, 0x0, 0x0, 0x821, 0x1b, 0x0, 0x0, 0x1, 0x0},
+			{".debug_info", SHT_PROGBITS, 0x0, 0x0, 0x83c, 0x11d, 0x0, 0x0, 0x1, 0x0},
+			{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0x959, 0x41, 0x0, 0x0, 0x1, 0x0},
+			{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0x99a, 0x35, 0x0, 0x0, 0x1, 0x0},
+			{".debug_frame", SHT_PROGBITS, 0x0, 0x0, 0x9d0, 0x30, 0x0, 0x0, 0x4, 0x0},
+			{".debug_str", SHT_PROGBITS, 0x0, 0x0, 0xa00, 0xd, 0x0, 0x0, 0x1, 0x0},
+			{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0xa0d, 0xf8, 0x0, 0x0, 0x1, 0x0},
+			{".symtab", SHT_SYMTAB, 0x0, 0x0, 0xfb8, 0x4b0, 0x1d, 0x38, 0x4, 0x10},
+			{".strtab", SHT_STRTAB, 0x0, 0x0, 0x1468, 0x206, 0x0, 0x0, 0x1, 0x0},
+		},
+	},
+	{
+		"testdata/gcc-amd64-linux-exec",
+		FileHeader{ELFCLASS64, ELFDATA2LSB, EV_CURRENT, ELFOSABI_NONE, 0, binary.LittleEndian, ET_EXEC, EM_X86_64},
+		[]SectionHeader{
+			{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+			{".interp", SHT_PROGBITS, SHF_ALLOC, 0x400200, 0x200, 0x1c, 0x0, 0x0, 0x1, 0x0},
+			{".note.ABI-tag", SHT_NOTE, SHF_ALLOC, 0x40021c, 0x21c, 0x20, 0x0, 0x0, 0x4, 0x0},
+			{".hash", SHT_HASH, SHF_ALLOC, 0x400240, 0x240, 0x24, 0x5, 0x0, 0x8, 0x4},
+			{".gnu.hash", SHT_LOOS + 268435446, SHF_ALLOC, 0x400268, 0x268, 0x1c, 0x5, 0x0, 0x8, 0x0},
+			{".dynsym", SHT_DYNSYM, SHF_ALLOC, 0x400288, 0x288, 0x60, 0x6, 0x1, 0x8, 0x18},
+			{".dynstr", SHT_STRTAB, SHF_ALLOC, 0x4002e8, 0x2e8, 0x3d, 0x0, 0x0, 0x1, 0x0},
+			{".gnu.version", SHT_HIOS, SHF_ALLOC, 0x400326, 0x326, 0x8, 0x5, 0x0, 0x2, 0x2},
+			{".gnu.version_r", SHT_LOOS + 268435454, SHF_ALLOC, 0x400330, 0x330, 0x20, 0x6, 0x1, 0x8, 0x0},
+			{".rela.dyn", SHT_RELA, SHF_ALLOC, 0x400350, 0x350, 0x18, 0x5, 0x0, 0x8, 0x18},
+			{".rela.plt", SHT_RELA, SHF_ALLOC, 0x400368, 0x368, 0x30, 0x5, 0xc, 0x8, 0x18},
+			{".init", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x400398, 0x398, 0x18, 0x0, 0x0, 0x4, 0x0},
+			{".plt", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x4003b0, 0x3b0, 0x30, 0x0, 0x0, 0x4, 0x10},
+			{".text", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x4003e0, 0x3e0, 0x1b4, 0x0, 0x0, 0x10, 0x0},
+			{".fini", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x400594, 0x594, 0xe, 0x0, 0x0, 0x4, 0x0},
+			{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x4005a4, 0x5a4, 0x11, 0x0, 0x0, 0x4, 0x0},
+			{".eh_frame_hdr", SHT_PROGBITS, SHF_ALLOC, 0x4005b8, 0x5b8, 0x24, 0x0, 0x0, 0x4, 0x0},
+			{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x4005e0, 0x5e0, 0xa4, 0x0, 0x0, 0x8, 0x0},
+			{".ctors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600688, 0x688, 0x10, 0x0, 0x0, 0x8, 0x0},
+			{".dtors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600698, 0x698, 0x10, 0x0, 0x0, 0x8, 0x0},
+			{".jcr", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x6006a8, 0x6a8, 0x8, 0x0, 0x0, 0x8, 0x0},
+			{".dynamic", SHT_DYNAMIC, SHF_WRITE + SHF_ALLOC, 0x6006b0, 0x6b0, 0x1a0, 0x6, 0x0, 0x8, 0x10},
+			{".got", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600850, 0x850, 0x8, 0x0, 0x0, 0x8, 0x8},
+			{".got.plt", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600858, 0x858, 0x28, 0x0, 0x0, 0x8, 0x8},
+			{".data", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600880, 0x880, 0x18, 0x0, 0x0, 0x8, 0x0},
+			{".bss", SHT_NOBITS, SHF_WRITE + SHF_ALLOC, 0x600898, 0x898, 0x8, 0x0, 0x0, 0x4, 0x0},
+			{".comment", SHT_PROGBITS, 0x0, 0x0, 0x898, 0x126, 0x0, 0x0, 0x1, 0x0},
+			{".debug_aranges", SHT_PROGBITS, 0x0, 0x0, 0x9c0, 0x90, 0x0, 0x0, 0x10, 0x0},
+			{".debug_pubnames", SHT_PROGBITS, 0x0, 0x0, 0xa50, 0x25, 0x0, 0x0, 0x1, 0x0},
+			{".debug_info", SHT_PROGBITS, 0x0, 0x0, 0xa75, 0x1a7, 0x0, 0x0, 0x1, 0x0},
+			{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0xc1c, 0x6f, 0x0, 0x0, 0x1, 0x0},
+			{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0xc8b, 0x13f, 0x0, 0x0, 0x1, 0x0},
+			{".debug_str", SHT_PROGBITS, SHF_MERGE + SHF_STRINGS, 0x0, 0xdca, 0xb1, 0x0, 0x0, 0x1, 0x1},
+			{".debug_ranges", SHT_PROGBITS, 0x0, 0x0, 0xe80, 0x90, 0x0, 0x0, 0x10, 0x0},
+			{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0xf10, 0x149, 0x0, 0x0, 0x1, 0x0},
+			{".symtab", SHT_SYMTAB, 0x0, 0x0, 0x19a0, 0x6f0, 0x24, 0x39, 0x8, 0x18},
+			{".strtab", SHT_STRTAB, 0x0, 0x0, 0x2090, 0x1fc, 0x0, 0x0, 0x1, 0x0},
+		},
+	},
+}
+
+func TestOpen(t *testing.T) {
+	for i := range fileTests {
+		tt := &fileTests[i]
+
+		f, err := Open(tt.file)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		if !reflect.DeepEqual(f.FileHeader, tt.hdr) {
+			t.Errorf("open %s:\n\thave %#v\n\twant %#v\n", tt.file, f.FileHeader, tt.hdr)
+			continue
+		}
+		for i, s := range f.Sections {
+			if i >= len(tt.sections) {
+				break
+			}
+			sh := &tt.sections[i]
+			if !reflect.DeepEqual(&s.SectionHeader, sh) {
+				t.Errorf("open %s, section %d:\n\thave %#v\n\twant %#v\n", tt.file, i, &s.SectionHeader, sh)
+			}
+		}
+		tn := len(tt.sections)
+		fn := len(f.Sections)
+		if tn != fn {
+			t.Errorf("open %s: len(Sections) = %d, want %d", tt.file, fn, tn)
+		}
+	}
+}
+
+type relocationTest struct {
+	file       string
+	firstEntry *dwarf.Entry
+}
+
+var relocationTests = []relocationTest{
+	{
+		"testdata/go-relocation-test-gcc441-x86-64.o",
+		&dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.4.1"}, {Attr: dwarf.AttrLanguage, Val: int64(1)}, {Attr: dwarf.AttrName, Val: "go-relocation-test.c"}, {Attr: dwarf.AttrCompDir, Val: "/tmp"}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0)}, {Attr: dwarf.AttrHighpc, Val: uint64(0x6)}, {Attr: dwarf.AttrStmtList, Val: int64(0)}}},
+	},
+	{
+		"testdata/go-relocation-test-gcc441-x86.o",
+		&dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.4.1"}, {Attr: dwarf.AttrLanguage, Val: int64(1)}, {Attr: dwarf.AttrName, Val: "t.c"}, {Attr: dwarf.AttrCompDir, Val: "/tmp"}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0)}, {Attr: dwarf.AttrHighpc, Val: uint64(0x5)}, {Attr: dwarf.AttrStmtList, Val: int64(0)}}},
+	},
+	{
+		"testdata/go-relocation-test-gcc424-x86-64.o",
+		&dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.2.4 (Ubuntu 4.2.4-1ubuntu4)"}, {Attr: dwarf.AttrLanguage, Val: int64(1)}, {Attr: dwarf.AttrName, Val: "go-relocation-test-gcc424.c"}, {Attr: dwarf.AttrCompDir, Val: "/tmp"}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0)}, {Attr: dwarf.AttrHighpc, Val: uint64(0x6)}, {Attr: dwarf.AttrStmtList, Val: int64(0)}}},
+	},
+}
+
+func TestDWARFRelocations(t *testing.T) {
+	for i, test := range relocationTests {
+		f, err := Open(test.file)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		dwarf, err := f.DWARF()
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		reader := dwarf.Reader()
+		// Checking only the first entry is sufficient since it has
+		// many different strings. If the relocation had failed, all
+		// the string offsets would be zero and all the strings would
+		// end up being the same.
+		firstEntry, err := reader.Next()
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+
+		if !reflect.DeepEqual(test.firstEntry, firstEntry) {
+			t.Errorf("#%d: mismatch: got:%#v want:%#v", i, firstEntry, test.firstEntry)
+			continue
+		}
+	}
+}
diff --git a/libgo/go/debug/elf/testdata/gcc-386-freebsd-exec b/libgo/go/debug/elf/testdata/gcc-386-freebsd-exec
new file mode 100755
index 000000000..7af9c58ca
--- /dev/null
+++ b/libgo/go/debug/elf/testdata/gcc-386-freebsd-exec
diff --git a/libgo/go/debug/elf/testdata/gcc-amd64-linux-exec b/libgo/go/debug/elf/testdata/gcc-amd64-linux-exec
new file mode 100755
index 000000000..c6cb1de28
--- /dev/null
+++ b/libgo/go/debug/elf/testdata/gcc-amd64-linux-exec
diff --git a/libgo/go/debug/elf/testdata/go-relocation-test-gcc424-x86-64.o b/libgo/go/debug/elf/testdata/go-relocation-test-gcc424-x86-64.o
new file mode 100644
index 000000000..a7c6d6e56
--- /dev/null
+++ b/libgo/go/debug/elf/testdata/go-relocation-test-gcc424-x86-64.o
diff --git a/libgo/go/debug/elf/testdata/go-relocation-test-gcc441-x86-64.o b/libgo/go/debug/elf/testdata/go-relocation-test-gcc441-x86-64.o
new file mode 100644
index 000000000..2d37ab6e6
--- /dev/null
+++ b/libgo/go/debug/elf/testdata/go-relocation-test-gcc441-x86-64.o
diff --git a/libgo/go/debug/elf/testdata/go-relocation-test-gcc441-x86.o b/libgo/go/debug/elf/testdata/go-relocation-test-gcc441-x86.o
new file mode 100644
index 000000000..0d59fe303
--- /dev/null
+++ b/libgo/go/debug/elf/testdata/go-relocation-test-gcc441-x86.o
diff --git a/libgo/go/debug/gosym/pclinetest.h b/libgo/go/debug/gosym/pclinetest.h
new file mode 100644
index 000000000..a6c40e76c
--- /dev/null
+++ b/libgo/go/debug/gosym/pclinetest.h
@@ -0,0 +1,7 @@
+// Empty include file to generate z symbols
+
+
+
+
+
+// EOF
diff --git a/libgo/go/debug/gosym/pclinetest.s b/libgo/go/debug/gosym/pclinetest.s
new file mode 100644
index 000000000..519656b63
--- /dev/null
+++ b/libgo/go/debug/gosym/pclinetest.s
@@ -0,0 +1,89 @@
+TEXT linefrompc(SB),7,$0	// Each byte stores its line delta
+BYTE $2;
+BYTE $1;
+BYTE $1; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1;
+BYTE $1;
+BYTE $1; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+BYTE $1; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+#include "pclinetest.h"
+BYTE $2;
+#include "pclinetest.h"
+BYTE $2;
+
+TEXT pcfromline(SB),7,$0	// Each record stores its line delta, then n, then n more bytes
+BYTE $31; BYTE $0;
+BYTE $1; BYTE $1; BYTE $0;
+BYTE $1; BYTE $0;
+
+BYTE $2; BYTE $4; BYTE $0; BYTE $0; BYTE $0; BYTE $0;
+
+
+#include "pclinetest.h"
+BYTE $4; BYTE $0;
+
+
+BYTE $3; BYTE $3; BYTE $0; BYTE $0; BYTE $0;
+#include "pclinetest.h"
+
+
+BYTE $4; BYTE $3; BYTE $0; BYTE $0; BYTE $0;
+
+TEXT main(SB),7,$0
+	// Prevent GC of our test symbols
+	CALL linefrompc(SB)
+	CALL pcfromline(SB)
+
+// Keep the linker happy
+TEXT runtime·morestack(SB),7,$0
+	RET
+
+TEXT runtime·morestack00(SB),7,$0
+	RET
+
+TEXT runtime·morestack10(SB),7,$0
+	RET
+
+TEXT runtime·morestack01(SB),7,$0
+	RET
+
+TEXT runtime·morestack11(SB),7,$0
+	RET
+
+TEXT runtime·morestack8(SB),7,$0
+	RET
+
+TEXT runtime·morestack16(SB),7,$0
+	RET
+
+TEXT runtime·morestack24(SB),7,$0
+	RET
+
+TEXT runtime·morestack32(SB),7,$0
+	RET
+
+TEXT runtime·morestack40(SB),7,$0
+	RET
+
+TEXT runtime·morestack48(SB),7,$0
+	RET
+
+TEXT runtime·morestack8(SB),7,$0
+	RET
+
diff --git a/libgo/go/debug/gosym/pclntab.go b/libgo/go/debug/gosym/pclntab.go
new file mode 100644
index 000000000..9d7b0d15f
--- /dev/null
+++ b/libgo/go/debug/gosym/pclntab.go
@@ -0,0 +1,82 @@
+// 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.
+
+/*
+ * Line tables
+ */
+
+package gosym
+
+import "encoding/binary"
+
+type LineTable struct {
+	Data []byte
+	PC   uint64
+	Line int
+}
+
+// TODO(rsc): Need to pull in quantum from architecture definition.
+const quantum = 1
+
+func (t *LineTable) parse(targetPC uint64, targetLine int) (b []byte, pc uint64, line int) {
+	// The PC/line table can be thought of as a sequence of
+	//  <pc update>* <line update>
+	// batches.  Each update batch results in a (pc, line) pair,
+	// where line applies to every PC from pc up to but not
+	// including the pc of the next pair.
+	//
+	// Here we process each update individually, which simplifies
+	// the code, but makes the corner cases more confusing.
+	b, pc, line = t.Data, t.PC, t.Line
+	for pc <= targetPC && line != targetLine && len(b) > 0 {
+		code := b[0]
+		b = b[1:]
+		switch {
+		case code == 0:
+			if len(b) < 4 {
+				b = b[0:0]
+				break
+			}
+			val := binary.BigEndian.Uint32(b)
+			b = b[4:]
+			line += int(val)
+		case code <= 64:
+			line += int(code)
+		case code <= 128:
+			line -= int(code - 64)
+		default:
+			pc += quantum * uint64(code-128)
+			continue
+		}
+		pc += quantum
+	}
+	return b, pc, line
+}
+
+func (t *LineTable) slice(pc uint64) *LineTable {
+	data, pc, line := t.parse(pc, -1)
+	return &LineTable{data, pc, line}
+}
+
+func (t *LineTable) PCToLine(pc uint64) int {
+	_, _, line := t.parse(pc, -1)
+	return line
+}
+
+func (t *LineTable) LineToPC(line int, maxpc uint64) uint64 {
+	_, pc, line1 := t.parse(maxpc, line)
+	if line1 != line {
+		return 0
+	}
+	// Subtract quantum from PC to account for post-line increment
+	return pc - quantum
+}
+
+// NewLineTable returns a new PC/line table
+// corresponding to the encoded data.
+// Text must be the start address of the
+// corresponding text segment.
+func NewLineTable(data []byte, text uint64) *LineTable {
+	return &LineTable{data, text, 0}
+}
diff --git a/libgo/go/debug/gosym/pclntab_test.go b/libgo/go/debug/gosym/pclntab_test.go
new file mode 100644
index 000000000..908702173
--- /dev/null
+++ b/libgo/go/debug/gosym/pclntab_test.go
@@ -0,0 +1,207 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gosym
+
+import (
+	"debug/elf"
+	"os"
+	"testing"
+	"syscall"
+)
+
+func dotest() bool {
+	// For now, only works on ELF platforms.
+	return syscall.OS == "linux" && os.Getenv("GOARCH") == "amd64"
+}
+
+func getTable(t *testing.T) *Table {
+	f, tab := crack(os.Args[0], t)
+	f.Close()
+	return tab
+}
+
+func crack(file string, t *testing.T) (*elf.File, *Table) {
+	// Open self
+	f, err := elf.Open(file)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return parse(file, f, t)
+}
+
+func parse(file string, f *elf.File, t *testing.T) (*elf.File, *Table) {
+	symdat, err := f.Section(".gosymtab").Data()
+	if err != nil {
+		f.Close()
+		t.Fatalf("reading %s gosymtab: %v", file, err)
+	}
+	pclndat, err := f.Section(".gopclntab").Data()
+	if err != nil {
+		f.Close()
+		t.Fatalf("reading %s gopclntab: %v", file, err)
+	}
+
+	pcln := NewLineTable(pclndat, f.Section(".text").Addr)
+	tab, err := NewTable(symdat, pcln)
+	if err != nil {
+		f.Close()
+		t.Fatalf("parsing %s gosymtab: %v", file, err)
+	}
+
+	return f, tab
+}
+
+var goarch = os.Getenv("O")
+
+func TestLineFromAline(t *testing.T) {
+	if !dotest() {
+		return
+	}
+
+	tab := getTable(t)
+
+	// Find the sym package
+	pkg := tab.LookupFunc("debug/gosym.TestLineFromAline").Obj
+	if pkg == nil {
+		t.Fatalf("nil pkg")
+	}
+
+	// Walk every absolute line and ensure that we hit every
+	// source line monotonically
+	lastline := make(map[string]int)
+	final := -1
+	for i := 0; i < 10000; i++ {
+		path, line := pkg.lineFromAline(i)
+		// Check for end of object
+		if path == "" {
+			if final == -1 {
+				final = i - 1
+			}
+			continue
+		} else if final != -1 {
+			t.Fatalf("reached end of package at absolute line %d, but absolute line %d mapped to %s:%d", final, i, path, line)
+		}
+		// It's okay to see files multiple times (e.g., sys.a)
+		if line == 1 {
+			lastline[path] = 1
+			continue
+		}
+		// Check that the is the next line in path
+		ll, ok := lastline[path]
+		if !ok {
+			t.Errorf("file %s starts on line %d", path, line)
+		} else if line != ll+1 {
+			t.Errorf("expected next line of file %s to be %d, got %d", path, ll+1, line)
+		}
+		lastline[path] = line
+	}
+	if final == -1 {
+		t.Errorf("never reached end of object")
+	}
+}
+
+func TestLineAline(t *testing.T) {
+	if !dotest() {
+		return
+	}
+
+	tab := getTable(t)
+
+	for _, o := range tab.Files {
+		// A source file can appear multiple times in a
+		// object.  alineFromLine will always return alines in
+		// the first file, so track which lines we've seen.
+		found := make(map[string]int)
+		for i := 0; i < 1000; i++ {
+			path, line := o.lineFromAline(i)
+			if path == "" {
+				break
+			}
+
+			// cgo files are full of 'Z' symbols, which we don't handle
+			if len(path) > 4 && path[len(path)-4:] == ".cgo" {
+				continue
+			}
+
+			if minline, ok := found[path]; path != "" && ok {
+				if minline >= line {
+					// We've already covered this file
+					continue
+				}
+			}
+			found[path] = line
+
+			a, err := o.alineFromLine(path, line)
+			if err != nil {
+				t.Errorf("absolute line %d in object %s maps to %s:%d, but mapping that back gives error %s", i, o.Paths[0].Name, path, line, err)
+			} else if a != i {
+				t.Errorf("absolute line %d in object %s maps to %s:%d, which maps back to absolute line %d\n", i, o.Paths[0].Name, path, line, a)
+			}
+		}
+	}
+}
+
+// gotest: if [ "$(uname)-$(uname -m)" = Linux-x86_64 -a "$GOARCH" = amd64 ]; then
+// gotest:    mkdir -p _test && $AS pclinetest.s && $LD -E main -o _test/pclinetest pclinetest.$O
+// gotest: fi
+func TestPCLine(t *testing.T) {
+	if !dotest() {
+		return
+	}
+
+	f, tab := crack("_test/pclinetest", t)
+	text := f.Section(".text")
+	textdat, err := text.Data()
+	if err != nil {
+		t.Fatalf("reading .text: %v", err)
+	}
+
+	// Test PCToLine
+	sym := tab.LookupFunc("linefrompc")
+	wantLine := 0
+	for pc := sym.Entry; pc < sym.End; pc++ {
+		file, line, fn := tab.PCToLine(pc)
+		off := pc - text.Addr // TODO(rsc): should not need off; bug in 8g
+		wantLine += int(textdat[off])
+		if fn == nil {
+			t.Errorf("failed to get line of PC %#x", pc)
+		} else if len(file) < 12 || file[len(file)-12:] != "pclinetest.s" || line != wantLine || fn != sym {
+			t.Errorf("expected %s:%d (%s) at PC %#x, got %s:%d (%s)", "pclinetest.s", wantLine, sym.Name, pc, file, line, fn.Name)
+		}
+	}
+
+	// Test LineToPC
+	sym = tab.LookupFunc("pcfromline")
+	lookupline := -1
+	wantLine = 0
+	off := uint64(0) // TODO(rsc): should not need off; bug in 8g
+	for pc := sym.Value; pc < sym.End; pc += 2 + uint64(textdat[off]) {
+		file, line, fn := tab.PCToLine(pc)
+		off = pc - text.Addr
+		wantLine += int(textdat[off])
+		if line != wantLine {
+			t.Errorf("expected line %d at PC %#x in pcfromline, got %d", wantLine, pc, line)
+			off = pc + 1 - text.Addr
+			continue
+		}
+		if lookupline == -1 {
+			lookupline = line
+		}
+		for ; lookupline <= line; lookupline++ {
+			pc2, fn2, err := tab.LineToPC(file, lookupline)
+			if lookupline != line {
+				// Should be nothing on this line
+				if err == nil {
+					t.Errorf("expected no PC at line %d, got %#x (%s)", lookupline, pc2, fn2.Name)
+				}
+			} else if err != nil {
+				t.Errorf("failed to get PC of line %d: %s", lookupline, err)
+			} else if pc != pc2 {
+				t.Errorf("expected PC %#x (%s) at line %d, got PC %#x (%s)", pc, fn.Name, line, pc2, fn2.Name)
+			}
+		}
+		off = pc + 1 - text.Addr
+	}
+}
diff --git a/libgo/go/debug/gosym/symtab.go b/libgo/go/debug/gosym/symtab.go
new file mode 100644
index 000000000..dea460d71
--- /dev/null
+++ b/libgo/go/debug/gosym/symtab.go
@@ -0,0 +1,548 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package gosym implements access to the Go symbol
+// and line number tables embedded in Go binaries generated
+// by the gc compilers.
+package gosym
+
+// The table format is a variant of the format used in Plan 9's a.out
+// format, documented at http://plan9.bell-labs.com/magic/man2html/6/a.out.
+// The best reference for the differences between the Plan 9 format
+// and the Go format is the runtime source, specifically ../../runtime/symtab.c.
+
+import (
+	"encoding/binary"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+/*
+ * Symbols
+ */
+
+// A Sym represents a single symbol table entry.
+type Sym struct {
+	Value  uint64
+	Type   byte
+	Name   string
+	GoType uint64
+	// If this symbol if a function symbol, the corresponding Func
+	Func *Func
+}
+
+// Static returns whether this symbol is static (not visible outside its file).
+func (s *Sym) Static() bool { return s.Type >= 'a' }
+
+// PackageName returns the package part of the symbol name,
+// or the empty string if there is none.
+func (s *Sym) PackageName() string {
+	if i := strings.Index(s.Name, "."); i != -1 {
+		return s.Name[0:i]
+	}
+	return ""
+}
+
+// ReceiverName returns the receiver type name of this symbol,
+// or the empty string if there is none.
+func (s *Sym) ReceiverName() string {
+	l := strings.Index(s.Name, ".")
+	r := strings.LastIndex(s.Name, ".")
+	if l == -1 || r == -1 || l == r {
+		return ""
+	}
+	return s.Name[l+1 : r]
+}
+
+// BaseName returns the symbol name without the package or receiver name.
+func (s *Sym) BaseName() string {
+	if i := strings.LastIndex(s.Name, "."); i != -1 {
+		return s.Name[i+1:]
+	}
+	return s.Name
+}
+
+// A Func collects information about a single function.
+type Func struct {
+	Entry uint64
+	*Sym
+	End       uint64
+	Params    []*Sym
+	Locals    []*Sym
+	FrameSize int
+	LineTable *LineTable
+	Obj       *Obj
+}
+
+// An Obj represents a single object file.
+type Obj struct {
+	Funcs []Func
+	Paths []Sym
+}
+
+/*
+ * Symbol tables
+ */
+
+// Table represents a Go symbol table.  It stores all of the
+// symbols decoded from the program and provides methods to translate
+// between symbols, names, and addresses.
+type Table struct {
+	Syms  []Sym
+	Funcs []Func
+	Files map[string]*Obj
+	Objs  []Obj
+	//	textEnd uint64;
+}
+
+type sym struct {
+	value  uint32
+	gotype uint32
+	typ    byte
+	name   []byte
+}
+
+func walksymtab(data []byte, fn func(sym) os.Error) os.Error {
+	var s sym
+	p := data
+	for len(p) >= 6 {
+		s.value = binary.BigEndian.Uint32(p[0:4])
+		typ := p[4]
+		if typ&0x80 == 0 {
+			return &DecodingError{len(data) - len(p) + 4, "bad symbol type", typ}
+		}
+		typ &^= 0x80
+		s.typ = typ
+		p = p[5:]
+		var i int
+		var nnul int
+		for i = 0; i < len(p); i++ {
+			if p[i] == 0 {
+				nnul = 1
+				break
+			}
+		}
+		switch typ {
+		case 'z', 'Z':
+			p = p[i+nnul:]
+			for i = 0; i+2 <= len(p); i += 2 {
+				if p[i] == 0 && p[i+1] == 0 {
+					nnul = 2
+					break
+				}
+			}
+		}
+		if i+nnul+4 > len(p) {
+			return &DecodingError{len(data), "unexpected EOF", nil}
+		}
+		s.name = p[0:i]
+		i += nnul
+		s.gotype = binary.BigEndian.Uint32(p[i : i+4])
+		p = p[i+4:]
+		fn(s)
+	}
+	return nil
+}
+
+// NewTable decodes the Go symbol table in data,
+// returning an in-memory representation.
+func NewTable(symtab []byte, pcln *LineTable) (*Table, os.Error) {
+	var n int
+	err := walksymtab(symtab, func(s sym) os.Error {
+		n++
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	var t Table
+	fname := make(map[uint16]string)
+	t.Syms = make([]Sym, 0, n)
+	nf := 0
+	nz := 0
+	lasttyp := uint8(0)
+	err = walksymtab(symtab, func(s sym) os.Error {
+		n := len(t.Syms)
+		t.Syms = t.Syms[0 : n+1]
+		ts := &t.Syms[n]
+		ts.Type = s.typ
+		ts.Value = uint64(s.value)
+		ts.GoType = uint64(s.gotype)
+		switch s.typ {
+		default:
+			// rewrite name to use . instead of · (c2 b7)
+			w := 0
+			b := s.name
+			for i := 0; i < len(b); i++ {
+				if b[i] == 0xc2 && i+1 < len(b) && b[i+1] == 0xb7 {
+					i++
+					b[i] = '.'
+				}
+				b[w] = b[i]
+				w++
+			}
+			ts.Name = string(s.name[0:w])
+		case 'z', 'Z':
+			if lasttyp != 'z' && lasttyp != 'Z' {
+				nz++
+			}
+			for i := 0; i < len(s.name); i += 2 {
+				eltIdx := binary.BigEndian.Uint16(s.name[i : i+2])
+				elt, ok := fname[eltIdx]
+				if !ok {
+					return &DecodingError{-1, "bad filename code", eltIdx}
+				}
+				if n := len(ts.Name); n > 0 && ts.Name[n-1] != '/' {
+					ts.Name += "/"
+				}
+				ts.Name += elt
+			}
+		}
+		switch s.typ {
+		case 'T', 't', 'L', 'l':
+			nf++
+		case 'f':
+			fname[uint16(s.value)] = ts.Name
+		}
+		lasttyp = s.typ
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	t.Funcs = make([]Func, 0, nf)
+	t.Objs = make([]Obj, 0, nz)
+	t.Files = make(map[string]*Obj)
+
+	// Count text symbols and attach frame sizes, parameters, and
+	// locals to them.  Also, find object file boundaries.
+	var obj *Obj
+	lastf := 0
+	for i := 0; i < len(t.Syms); i++ {
+		sym := &t.Syms[i]
+		switch sym.Type {
+		case 'Z', 'z': // path symbol
+			// Finish the current object
+			if obj != nil {
+				obj.Funcs = t.Funcs[lastf:]
+			}
+			lastf = len(t.Funcs)
+
+			// Start new object
+			n := len(t.Objs)
+			t.Objs = t.Objs[0 : n+1]
+			obj = &t.Objs[n]
+
+			// Count & copy path symbols
+			var end int
+			for end = i + 1; end < len(t.Syms); end++ {
+				if c := t.Syms[end].Type; c != 'Z' && c != 'z' {
+					break
+				}
+			}
+			obj.Paths = t.Syms[i:end]
+			i = end - 1 // loop will i++
+
+			// Record file names
+			depth := 0
+			for j := range obj.Paths {
+				s := &obj.Paths[j]
+				if s.Name == "" {
+					depth--
+				} else {
+					if depth == 0 {
+						t.Files[s.Name] = obj
+					}
+					depth++
+				}
+			}
+
+		case 'T', 't', 'L', 'l': // text symbol
+			if n := len(t.Funcs); n > 0 {
+				t.Funcs[n-1].End = sym.Value
+			}
+			if sym.Name == "etext" {
+				continue
+			}
+
+			// Count parameter and local (auto) syms
+			var np, na int
+			var end int
+		countloop:
+			for end = i + 1; end < len(t.Syms); end++ {
+				switch t.Syms[end].Type {
+				case 'T', 't', 'L', 'l', 'Z', 'z':
+					break countloop
+				case 'p':
+					np++
+				case 'a':
+					na++
+				}
+			}
+
+			// Fill in the function symbol
+			n := len(t.Funcs)
+			t.Funcs = t.Funcs[0 : n+1]
+			fn := &t.Funcs[n]
+			sym.Func = fn
+			fn.Params = make([]*Sym, 0, np)
+			fn.Locals = make([]*Sym, 0, na)
+			fn.Sym = sym
+			fn.Entry = sym.Value
+			fn.Obj = obj
+			if pcln != nil {
+				fn.LineTable = pcln.slice(fn.Entry)
+				pcln = fn.LineTable
+			}
+			for j := i; j < end; j++ {
+				s := &t.Syms[j]
+				switch s.Type {
+				case 'm':
+					fn.FrameSize = int(s.Value)
+				case 'p':
+					n := len(fn.Params)
+					fn.Params = fn.Params[0 : n+1]
+					fn.Params[n] = s
+				case 'a':
+					n := len(fn.Locals)
+					fn.Locals = fn.Locals[0 : n+1]
+					fn.Locals[n] = s
+				}
+			}
+			i = end - 1 // loop will i++
+		}
+	}
+	if obj != nil {
+		obj.Funcs = t.Funcs[lastf:]
+	}
+	return &t, nil
+}
+
+// PCToFunc returns the function containing the program counter pc,
+// or nil if there is no such function.
+func (t *Table) PCToFunc(pc uint64) *Func {
+	funcs := t.Funcs
+	for len(funcs) > 0 {
+		m := len(funcs) / 2
+		fn := &funcs[m]
+		switch {
+		case pc < fn.Entry:
+			funcs = funcs[0:m]
+		case fn.Entry <= pc && pc < fn.End:
+			return fn
+		default:
+			funcs = funcs[m+1:]
+		}
+	}
+	return nil
+}
+
+// PCToLine looks up line number information for a program counter.
+// If there is no information, it returns fn == nil.
+func (t *Table) PCToLine(pc uint64) (file string, line int, fn *Func) {
+	if fn = t.PCToFunc(pc); fn == nil {
+		return
+	}
+	file, line = fn.Obj.lineFromAline(fn.LineTable.PCToLine(pc))
+	return
+}
+
+// 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) {
+	obj, ok := t.Files[file]
+	if !ok {
+		return 0, nil, UnknownFileError(file)
+	}
+	abs, err := obj.alineFromLine(file, line)
+	if err != nil {
+		return
+	}
+	for i := range obj.Funcs {
+		f := &obj.Funcs[i]
+		pc := f.LineTable.LineToPC(abs, f.End)
+		if pc != 0 {
+			return pc, f, nil
+		}
+	}
+	return 0, nil, &UnknownLineError{file, line}
+}
+
+// LookupSym returns the text, data, or bss symbol with the given name,
+// or nil if no such symbol is found.
+func (t *Table) LookupSym(name string) *Sym {
+	// TODO(austin) Maybe make a map
+	for i := range t.Syms {
+		s := &t.Syms[i]
+		switch s.Type {
+		case 'T', 't', 'L', 'l', 'D', 'd', 'B', 'b':
+			if s.Name == name {
+				return s
+			}
+		}
+	}
+	return nil
+}
+
+// LookupFunc returns the text, data, or bss symbol with the given name,
+// or nil if no such symbol is found.
+func (t *Table) LookupFunc(name string) *Func {
+	for i := range t.Funcs {
+		f := &t.Funcs[i]
+		if f.Sym.Name == name {
+			return f
+		}
+	}
+	return nil
+}
+
+// SymByAddr returns the text, data, or bss symbol starting at the given address.
+// TODO(rsc): Allow lookup by any address within the symbol.
+func (t *Table) SymByAddr(addr uint64) *Sym {
+	// TODO(austin) Maybe make a map
+	for i := range t.Syms {
+		s := &t.Syms[i]
+		switch s.Type {
+		case 'T', 't', 'L', 'l', 'D', 'd', 'B', 'b':
+			if s.Value == addr {
+				return s
+			}
+		}
+	}
+	return nil
+}
+
+/*
+ * Object files
+ */
+
+func (o *Obj) lineFromAline(aline int) (string, int) {
+	type stackEnt struct {
+		path   string
+		start  int
+		offset int
+		prev   *stackEnt
+	}
+
+	noPath := &stackEnt{"", 0, 0, nil}
+	tos := noPath
+
+	// TODO(austin) I have no idea how 'Z' symbols work, except
+	// that they pop the stack.
+pathloop:
+	for _, s := range o.Paths {
+		val := int(s.Value)
+		switch {
+		case val > aline:
+			break pathloop
+
+		case val == 1:
+			// Start a new stack
+			tos = &stackEnt{s.Name, val, 0, noPath}
+
+		case s.Name == "":
+			// Pop
+			if tos == noPath {
+				return "<malformed symbol table>", 0
+			}
+			tos.prev.offset += val - tos.start
+			tos = tos.prev
+
+		default:
+			// Push
+			tos = &stackEnt{s.Name, val, 0, tos}
+		}
+	}
+
+	if tos == noPath {
+		return "", 0
+	}
+	return tos.path, aline - tos.start - tos.offset + 1
+}
+
+func (o *Obj) alineFromLine(path string, line int) (int, os.Error) {
+	if line < 1 {
+		return 0, &UnknownLineError{path, line}
+	}
+
+	for i, s := range o.Paths {
+		// Find this path
+		if s.Name != path {
+			continue
+		}
+
+		// Find this line at this stack level
+		depth := 0
+		var incstart int
+		line += int(s.Value)
+	pathloop:
+		for _, s := range o.Paths[i:] {
+			val := int(s.Value)
+			switch {
+			case depth == 1 && val >= line:
+				return line - 1, nil
+
+			case s.Name == "":
+				depth--
+				if depth == 0 {
+					break pathloop
+				} else if depth == 1 {
+					line += val - incstart
+				}
+
+			default:
+				if depth == 1 {
+					incstart = val
+				}
+				depth++
+			}
+		}
+		return 0, &UnknownLineError{path, line}
+	}
+	return 0, UnknownFileError(path)
+}
+
+/*
+ * Errors
+ */
+
+// UnknownFileError represents a failure to find the specific file in
+// the symbol table.
+type UnknownFileError string
+
+func (e UnknownFileError) String() 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
+// or because there is no code on the given line.
+type UnknownLineError struct {
+	File string
+	Line int
+}
+
+func (e *UnknownLineError) String() string {
+	return "no code at " + e.File + ":" + strconv.Itoa(e.Line)
+}
+
+// DecodingError represents an error during the decoding of
+// the symbol table.
+type DecodingError struct {
+	off int
+	msg string
+	val interface{}
+}
+
+func (e *DecodingError) String() string {
+	msg := e.msg
+	if e.val != nil {
+		msg += fmt.Sprintf(" '%v'", e.val)
+	}
+	msg += fmt.Sprintf(" at byte %#x", e.off)
+	return msg
+}
diff --git a/libgo/go/debug/macho/file.go b/libgo/go/debug/macho/file.go
new file mode 100644
index 000000000..fd8da9449
--- /dev/null
+++ b/libgo/go/debug/macho/file.go
@@ -0,0 +1,517 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package macho implements access to Mach-O object files, as defined by
+// http://developer.apple.com/mac/library/documentation/DeveloperTools/Conceptual/MachORuntime/Reference/reference.html.
+package macho
+
+// High level access to low level data structures.
+
+import (
+	"bytes"
+	"debug/dwarf"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"os"
+)
+
+// A File represents an open Mach-O file.
+type File struct {
+	FileHeader
+	ByteOrder binary.ByteOrder
+	Loads     []Load
+	Sections  []*Section
+
+	Symtab   *Symtab
+	Dysymtab *Dysymtab
+
+	closer io.Closer
+}
+
+// A Load represents any Mach-O load command.
+type Load interface {
+	Raw() []byte
+}
+
+// A LoadBytes is the uninterpreted bytes of a Mach-O load command.
+type LoadBytes []byte
+
+func (b LoadBytes) Raw() []byte { return b }
+
+// A SegmentHeader is the header for a Mach-O 32-bit or 64-bit load segment command.
+type SegmentHeader struct {
+	Cmd     LoadCmd
+	Len     uint32
+	Name    string
+	Addr    uint64
+	Memsz   uint64
+	Offset  uint64
+	Filesz  uint64
+	Maxprot uint32
+	Prot    uint32
+	Nsect   uint32
+	Flag    uint32
+}
+
+// A Segment represents a Mach-O 32-bit or 64-bit load segment command.
+type Segment struct {
+	LoadBytes
+	SegmentHeader
+
+	// Embed ReaderAt for ReadAt method.
+	// Do not embed SectionReader directly
+	// to avoid having Read and Seek.
+	// If a client wants Read and Seek it must use
+	// Open() to avoid fighting over the seek offset
+	// with other clients.
+	io.ReaderAt
+	sr *io.SectionReader
+}
+
+// Data reads and returns the contents of the segment.
+func (s *Segment) Data() ([]byte, os.Error) {
+	dat := make([]byte, s.sr.Size())
+	n, err := s.sr.ReadAt(dat, 0)
+	return dat[0:n], err
+}
+
+// Open returns a new ReadSeeker reading the segment.
+func (s *Segment) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) }
+
+type SectionHeader struct {
+	Name   string
+	Seg    string
+	Addr   uint64
+	Size   uint64
+	Offset uint32
+	Align  uint32
+	Reloff uint32
+	Nreloc uint32
+	Flags  uint32
+}
+
+type Section struct {
+	SectionHeader
+
+	// Embed ReaderAt for ReadAt method.
+	// Do not embed SectionReader directly
+	// to avoid having Read and Seek.
+	// If a client wants Read and Seek it must use
+	// Open() to avoid fighting over the seek offset
+	// with other clients.
+	io.ReaderAt
+	sr *io.SectionReader
+}
+
+// Data reads and returns the contents of the Mach-O section.
+func (s *Section) Data() ([]byte, os.Error) {
+	dat := make([]byte, s.sr.Size())
+	n, err := s.sr.ReadAt(dat, 0)
+	return dat[0:n], err
+}
+
+// Open returns a new ReadSeeker reading the Mach-O section.
+func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) }
+
+// A Dylib represents a Mach-O load dynamic library command.
+type Dylib struct {
+	LoadBytes
+	Name           string
+	Time           uint32
+	CurrentVersion uint32
+	CompatVersion  uint32
+}
+
+// A Symtab represents a Mach-O symbol table command.
+type Symtab struct {
+	LoadBytes
+	SymtabCmd
+	Syms []Symbol
+}
+
+// A Dysymtab represents a Mach-O dynamic symbol table command.
+type Dysymtab struct {
+	LoadBytes
+	DysymtabCmd
+	IndirectSyms []uint32 // indices into Symtab.Syms
+}
+
+/*
+ * Mach-O reader
+ */
+
+type FormatError struct {
+	off int64
+	msg string
+	val interface{}
+}
+
+func (e *FormatError) String() string {
+	msg := e.msg
+	if e.val != nil {
+		msg += fmt.Sprintf(" '%v'", e.val)
+	}
+	msg += fmt.Sprintf(" in record at byte %#x", e.off)
+	return msg
+}
+
+// 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) {
+	f, err := os.Open(name, os.O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+	ff, err := NewFile(f)
+	if err != nil {
+		f.Close()
+		return nil, err
+	}
+	ff.closer = f
+	return ff, nil
+}
+
+// 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
+	if f.closer != nil {
+		err = f.closer.Close()
+		f.closer = nil
+	}
+	return err
+}
+
+// NewFile creates a new File for acecssing 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) {
+	f := new(File)
+	sr := io.NewSectionReader(r, 0, 1<<63-1)
+
+	// Read and decode Mach magic to determine byte order, size.
+	// Magic32 and Magic64 differ only in the bottom bit.
+	var ident [4]byte
+	if _, err := r.ReadAt(ident[0:], 0); err != nil {
+		return nil, err
+	}
+	be := binary.BigEndian.Uint32(ident[0:])
+	le := binary.LittleEndian.Uint32(ident[0:])
+	switch Magic32 &^ 1 {
+	case be &^ 1:
+		f.ByteOrder = binary.BigEndian
+		f.Magic = be
+	case le &^ 1:
+		f.ByteOrder = binary.LittleEndian
+		f.Magic = le
+	default:
+		return nil, &FormatError{0, "invalid magic number", nil}
+	}
+
+	// Read entire file header.
+	if err := binary.Read(sr, f.ByteOrder, &f.FileHeader); err != nil {
+		return nil, err
+	}
+
+	// Then load commands.
+	offset := int64(fileHeaderSize32)
+	if f.Magic == Magic64 {
+		offset = fileHeaderSize64
+	}
+	dat := make([]byte, f.Cmdsz)
+	if _, err := r.ReadAt(dat, offset); err != nil {
+		return nil, err
+	}
+	f.Loads = make([]Load, f.Ncmd)
+	bo := f.ByteOrder
+	for i := range f.Loads {
+		// Each load command begins with uint32 command and length.
+		if len(dat) < 8 {
+			return nil, &FormatError{offset, "command block too small", nil}
+		}
+		cmd, siz := LoadCmd(bo.Uint32(dat[0:4])), bo.Uint32(dat[4:8])
+		if siz < 8 || siz > uint32(len(dat)) {
+			return nil, &FormatError{offset, "invalid command block size", nil}
+		}
+		var cmddat []byte
+		cmddat, dat = dat[0:siz], dat[siz:]
+		offset += int64(siz)
+		var s *Segment
+		switch cmd {
+		default:
+			f.Loads[i] = LoadBytes(cmddat)
+
+		case LoadCmdDylib:
+			var hdr DylibCmd
+			b := bytes.NewBuffer(cmddat)
+			if err := binary.Read(b, bo, &hdr); err != nil {
+				return nil, err
+			}
+			l := new(Dylib)
+			if hdr.Name >= uint32(len(cmddat)) {
+				return nil, &FormatError{offset, "invalid name in dynamic library command", hdr.Name}
+			}
+			l.Name = cstring(cmddat[hdr.Name:])
+			l.Time = hdr.Time
+			l.CurrentVersion = hdr.CurrentVersion
+			l.CompatVersion = hdr.CompatVersion
+			l.LoadBytes = LoadBytes(cmddat)
+			f.Loads[i] = l
+
+		case LoadCmdSymtab:
+			var hdr SymtabCmd
+			b := bytes.NewBuffer(cmddat)
+			if err := binary.Read(b, bo, &hdr); err != nil {
+				return nil, err
+			}
+			strtab := make([]byte, hdr.Strsize)
+			if _, err := r.ReadAt(strtab, int64(hdr.Stroff)); err != nil {
+				return nil, err
+			}
+			var symsz int
+			if f.Magic == Magic64 {
+				symsz = 16
+			} else {
+				symsz = 12
+			}
+			symdat := make([]byte, int(hdr.Nsyms)*symsz)
+			if _, err := r.ReadAt(symdat, int64(hdr.Symoff)); err != nil {
+				return nil, err
+			}
+			st, err := f.parseSymtab(symdat, strtab, cmddat, &hdr, offset)
+			if err != nil {
+				return nil, err
+			}
+			f.Loads[i] = st
+			f.Symtab = st
+
+		case LoadCmdDysymtab:
+			var hdr DysymtabCmd
+			b := bytes.NewBuffer(cmddat)
+			if err := binary.Read(b, bo, &hdr); err != nil {
+				return nil, err
+			}
+			dat := make([]byte, hdr.Nindirectsyms*4)
+			if _, err := r.ReadAt(dat, int64(hdr.Indirectsymoff)); err != nil {
+				return nil, err
+			}
+			x := make([]uint32, hdr.Nindirectsyms)
+			if err := binary.Read(bytes.NewBuffer(dat), bo, x); err != nil {
+				return nil, err
+			}
+			st := new(Dysymtab)
+			st.LoadBytes = LoadBytes(cmddat)
+			st.DysymtabCmd = hdr
+			st.IndirectSyms = x
+			f.Loads[i] = st
+			f.Dysymtab = st
+
+		case LoadCmdSegment:
+			var seg32 Segment32
+			b := bytes.NewBuffer(cmddat)
+			if err := binary.Read(b, bo, &seg32); err != nil {
+				return nil, err
+			}
+			s = new(Segment)
+			s.LoadBytes = cmddat
+			s.Cmd = cmd
+			s.Len = siz
+			s.Name = cstring(seg32.Name[0:])
+			s.Addr = uint64(seg32.Addr)
+			s.Memsz = uint64(seg32.Memsz)
+			s.Offset = uint64(seg32.Offset)
+			s.Filesz = uint64(seg32.Filesz)
+			s.Maxprot = seg32.Maxprot
+			s.Prot = seg32.Prot
+			s.Nsect = seg32.Nsect
+			s.Flag = seg32.Flag
+			f.Loads[i] = s
+			for i := 0; i < int(s.Nsect); i++ {
+				var sh32 Section32
+				if err := binary.Read(b, bo, &sh32); err != nil {
+					return nil, err
+				}
+				sh := new(Section)
+				sh.Name = cstring(sh32.Name[0:])
+				sh.Seg = cstring(sh32.Seg[0:])
+				sh.Addr = uint64(sh32.Addr)
+				sh.Size = uint64(sh32.Size)
+				sh.Offset = sh32.Offset
+				sh.Align = sh32.Align
+				sh.Reloff = sh32.Reloff
+				sh.Nreloc = sh32.Nreloc
+				sh.Flags = sh32.Flags
+				f.pushSection(sh, r)
+			}
+
+		case LoadCmdSegment64:
+			var seg64 Segment64
+			b := bytes.NewBuffer(cmddat)
+			if err := binary.Read(b, bo, &seg64); err != nil {
+				return nil, err
+			}
+			s = new(Segment)
+			s.LoadBytes = cmddat
+			s.Cmd = cmd
+			s.Len = siz
+			s.Name = cstring(seg64.Name[0:])
+			s.Addr = seg64.Addr
+			s.Memsz = seg64.Memsz
+			s.Offset = seg64.Offset
+			s.Filesz = seg64.Filesz
+			s.Maxprot = seg64.Maxprot
+			s.Prot = seg64.Prot
+			s.Nsect = seg64.Nsect
+			s.Flag = seg64.Flag
+			f.Loads[i] = s
+			for i := 0; i < int(s.Nsect); i++ {
+				var sh64 Section64
+				if err := binary.Read(b, bo, &sh64); err != nil {
+					return nil, err
+				}
+				sh := new(Section)
+				sh.Name = cstring(sh64.Name[0:])
+				sh.Seg = cstring(sh64.Seg[0:])
+				sh.Addr = sh64.Addr
+				sh.Size = sh64.Size
+				sh.Offset = sh64.Offset
+				sh.Align = sh64.Align
+				sh.Reloff = sh64.Reloff
+				sh.Nreloc = sh64.Nreloc
+				sh.Flags = sh64.Flags
+				f.pushSection(sh, r)
+			}
+		}
+		if s != nil {
+			s.sr = io.NewSectionReader(r, int64(s.Offset), int64(s.Filesz))
+			s.ReaderAt = s.sr
+		}
+	}
+	return f, nil
+}
+
+func (f *File) parseSymtab(symdat, strtab, cmddat []byte, hdr *SymtabCmd, offset int64) (*Symtab, os.Error) {
+	bo := f.ByteOrder
+	symtab := make([]Symbol, hdr.Nsyms)
+	b := bytes.NewBuffer(symdat)
+	for i := range symtab {
+		var n Nlist64
+		if f.Magic == Magic64 {
+			if err := binary.Read(b, bo, &n); err != nil {
+				return nil, err
+			}
+		} else {
+			var n32 Nlist32
+			if err := binary.Read(b, bo, &n32); err != nil {
+				return nil, err
+			}
+			n.Name = n32.Name
+			n.Type = n32.Type
+			n.Sect = n32.Sect
+			n.Desc = n32.Desc
+			n.Value = uint64(n32.Value)
+		}
+		sym := &symtab[i]
+		if n.Name >= uint32(len(strtab)) {
+			return nil, &FormatError{offset, "invalid name in symbol table", n.Name}
+		}
+		sym.Name = cstring(strtab[n.Name:])
+		sym.Type = n.Type
+		sym.Sect = n.Sect
+		sym.Desc = n.Desc
+		sym.Value = n.Value
+	}
+	st := new(Symtab)
+	st.LoadBytes = LoadBytes(cmddat)
+	st.Syms = symtab
+	return st, nil
+}
+
+func (f *File) pushSection(sh *Section, r io.ReaderAt) {
+	f.Sections = append(f.Sections, sh)
+	sh.sr = io.NewSectionReader(r, int64(sh.Offset), int64(sh.Size))
+	sh.ReaderAt = sh.sr
+}
+
+func cstring(b []byte) string {
+	var i int
+	for i = 0; i < len(b) && b[i] != 0; i++ {
+	}
+	return string(b[0:i])
+}
+
+// Segment returns the first Segment with the given name, or nil if no such segment exists.
+func (f *File) Segment(name string) *Segment {
+	for _, l := range f.Loads {
+		if s, ok := l.(*Segment); ok && s.Name == name {
+			return s
+		}
+	}
+	return nil
+}
+
+// Section returns the first section with the given name, or nil if no such
+// section exists.
+func (f *File) Section(name string) *Section {
+	for _, s := range f.Sections {
+		if s.Name == name {
+			return s
+		}
+	}
+	return nil
+}
+
+// DWARF returns the DWARF debug information for the Mach-O file.
+func (f *File) DWARF() (*dwarf.Data, os.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.
+	var names = [...]string{"abbrev", "info", "str"}
+	var dat [len(names)][]byte
+	for i, name := range names {
+		name = "__debug_" + name
+		s := f.Section(name)
+		if s == nil {
+			return nil, os.NewError("missing Mach-O section " + name)
+		}
+		b, err := s.Data()
+		if err != nil && uint64(len(b)) < s.Size {
+			return nil, err
+		}
+		dat[i] = b
+	}
+
+	abbrev, info, str := dat[0], dat[1], dat[2]
+	return dwarf.New(abbrev, nil, nil, info, nil, nil, nil, str)
+}
+
+// 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) {
+	if f.Dysymtab == nil || f.Symtab == nil {
+		return nil, &FormatError{0, "missing symbol table", nil}
+	}
+
+	st := f.Symtab
+	dt := f.Dysymtab
+	var all []string
+	for _, s := range st.Syms[dt.Iundefsym : dt.Iundefsym+dt.Nundefsym] {
+		all = append(all, s.Name)
+	}
+	return all, nil
+}
+
+// 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) {
+	var all []string
+	for _, l := range f.Loads {
+		if lib, ok := l.(*Dylib); ok {
+			all = append(all, lib.Name)
+		}
+	}
+	return all, nil
+}
diff --git a/libgo/go/debug/macho/file_test.go b/libgo/go/debug/macho/file_test.go
new file mode 100644
index 000000000..56d8a20be
--- /dev/null
+++ b/libgo/go/debug/macho/file_test.go
@@ -0,0 +1,167 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package macho
+
+import (
+	"reflect"
+	"testing"
+)
+
+type fileTest struct {
+	file     string
+	hdr      FileHeader
+	segments []*SegmentHeader
+	sections []*SectionHeader
+}
+
+var fileTests = []fileTest{
+	{
+		"testdata/gcc-386-darwin-exec",
+		FileHeader{0xfeedface, Cpu386, 0x3, 0x2, 0xc, 0x3c0, 0x85},
+		[]*SegmentHeader{
+			&SegmentHeader{LoadCmdSegment, 0x38, "__PAGEZERO", 0x0, 0x1000, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+			&SegmentHeader{LoadCmdSegment, 0xc0, "__TEXT", 0x1000, 0x1000, 0x0, 0x1000, 0x7, 0x5, 0x2, 0x0},
+			&SegmentHeader{LoadCmdSegment, 0xc0, "__DATA", 0x2000, 0x1000, 0x1000, 0x1000, 0x7, 0x3, 0x2, 0x0},
+			&SegmentHeader{LoadCmdSegment, 0x7c, "__IMPORT", 0x3000, 0x1000, 0x2000, 0x1000, 0x7, 0x7, 0x1, 0x0},
+			&SegmentHeader{LoadCmdSegment, 0x38, "__LINKEDIT", 0x4000, 0x1000, 0x3000, 0x12c, 0x7, 0x1, 0x0, 0x0},
+			nil,
+			nil,
+			nil,
+			nil,
+			nil,
+			nil,
+			nil,
+		},
+		[]*SectionHeader{
+			&SectionHeader{"__text", "__TEXT", 0x1f68, 0x88, 0xf68, 0x2, 0x0, 0x0, 0x80000400},
+			&SectionHeader{"__cstring", "__TEXT", 0x1ff0, 0xd, 0xff0, 0x0, 0x0, 0x0, 0x2},
+			&SectionHeader{"__data", "__DATA", 0x2000, 0x14, 0x1000, 0x2, 0x0, 0x0, 0x0},
+			&SectionHeader{"__dyld", "__DATA", 0x2014, 0x1c, 0x1014, 0x2, 0x0, 0x0, 0x0},
+			&SectionHeader{"__jump_table", "__IMPORT", 0x3000, 0xa, 0x2000, 0x6, 0x0, 0x0, 0x4000008},
+		},
+	},
+	{
+		"testdata/gcc-amd64-darwin-exec",
+		FileHeader{0xfeedfacf, CpuAmd64, 0x80000003, 0x2, 0xb, 0x568, 0x85},
+		[]*SegmentHeader{
+			&SegmentHeader{LoadCmdSegment64, 0x48, "__PAGEZERO", 0x0, 0x100000000, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+			&SegmentHeader{LoadCmdSegment64, 0x1d8, "__TEXT", 0x100000000, 0x1000, 0x0, 0x1000, 0x7, 0x5, 0x5, 0x0},
+			&SegmentHeader{LoadCmdSegment64, 0x138, "__DATA", 0x100001000, 0x1000, 0x1000, 0x1000, 0x7, 0x3, 0x3, 0x0},
+			&SegmentHeader{LoadCmdSegment64, 0x48, "__LINKEDIT", 0x100002000, 0x1000, 0x2000, 0x140, 0x7, 0x1, 0x0, 0x0},
+			nil,
+			nil,
+			nil,
+			nil,
+			nil,
+			nil,
+			nil,
+		},
+		[]*SectionHeader{
+			&SectionHeader{"__text", "__TEXT", 0x100000f14, 0x6d, 0xf14, 0x2, 0x0, 0x0, 0x80000400},
+			&SectionHeader{"__symbol_stub1", "__TEXT", 0x100000f81, 0xc, 0xf81, 0x0, 0x0, 0x0, 0x80000408},
+			&SectionHeader{"__stub_helper", "__TEXT", 0x100000f90, 0x18, 0xf90, 0x2, 0x0, 0x0, 0x0},
+			&SectionHeader{"__cstring", "__TEXT", 0x100000fa8, 0xd, 0xfa8, 0x0, 0x0, 0x0, 0x2},
+			&SectionHeader{"__eh_frame", "__TEXT", 0x100000fb8, 0x48, 0xfb8, 0x3, 0x0, 0x0, 0x6000000b},
+			&SectionHeader{"__data", "__DATA", 0x100001000, 0x1c, 0x1000, 0x3, 0x0, 0x0, 0x0},
+			&SectionHeader{"__dyld", "__DATA", 0x100001020, 0x38, 0x1020, 0x3, 0x0, 0x0, 0x0},
+			&SectionHeader{"__la_symbol_ptr", "__DATA", 0x100001058, 0x10, 0x1058, 0x2, 0x0, 0x0, 0x7},
+		},
+	},
+	{
+		"testdata/gcc-amd64-darwin-exec-debug",
+		FileHeader{0xfeedfacf, CpuAmd64, 0x80000003, 0xa, 0x4, 0x5a0, 0},
+		[]*SegmentHeader{
+			nil,
+			&SegmentHeader{LoadCmdSegment64, 0x1d8, "__TEXT", 0x100000000, 0x1000, 0x0, 0x0, 0x7, 0x5, 0x5, 0x0},
+			&SegmentHeader{LoadCmdSegment64, 0x138, "__DATA", 0x100001000, 0x1000, 0x0, 0x0, 0x7, 0x3, 0x3, 0x0},
+			&SegmentHeader{LoadCmdSegment64, 0x278, "__DWARF", 0x100002000, 0x1000, 0x1000, 0x1bc, 0x7, 0x3, 0x7, 0x0},
+		},
+		[]*SectionHeader{
+			&SectionHeader{"__text", "__TEXT", 0x100000f14, 0x0, 0x0, 0x2, 0x0, 0x0, 0x80000400},
+			&SectionHeader{"__symbol_stub1", "__TEXT", 0x100000f81, 0x0, 0x0, 0x0, 0x0, 0x0, 0x80000408},
+			&SectionHeader{"__stub_helper", "__TEXT", 0x100000f90, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0},
+			&SectionHeader{"__cstring", "__TEXT", 0x100000fa8, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2},
+			&SectionHeader{"__eh_frame", "__TEXT", 0x100000fb8, 0x0, 0x0, 0x3, 0x0, 0x0, 0x6000000b},
+			&SectionHeader{"__data", "__DATA", 0x100001000, 0x0, 0x0, 0x3, 0x0, 0x0, 0x0},
+			&SectionHeader{"__dyld", "__DATA", 0x100001020, 0x0, 0x0, 0x3, 0x0, 0x0, 0x0},
+			&SectionHeader{"__la_symbol_ptr", "__DATA", 0x100001058, 0x0, 0x0, 0x2, 0x0, 0x0, 0x7},
+			&SectionHeader{"__debug_abbrev", "__DWARF", 0x100002000, 0x36, 0x1000, 0x0, 0x0, 0x0, 0x0},
+			&SectionHeader{"__debug_aranges", "__DWARF", 0x100002036, 0x30, 0x1036, 0x0, 0x0, 0x0, 0x0},
+			&SectionHeader{"__debug_frame", "__DWARF", 0x100002066, 0x40, 0x1066, 0x0, 0x0, 0x0, 0x0},
+			&SectionHeader{"__debug_info", "__DWARF", 0x1000020a6, 0x54, 0x10a6, 0x0, 0x0, 0x0, 0x0},
+			&SectionHeader{"__debug_line", "__DWARF", 0x1000020fa, 0x47, 0x10fa, 0x0, 0x0, 0x0, 0x0},
+			&SectionHeader{"__debug_pubnames", "__DWARF", 0x100002141, 0x1b, 0x1141, 0x0, 0x0, 0x0, 0x0},
+			&SectionHeader{"__debug_str", "__DWARF", 0x10000215c, 0x60, 0x115c, 0x0, 0x0, 0x0, 0x0},
+		},
+	},
+}
+
+func TestOpen(t *testing.T) {
+	for i := range fileTests {
+		tt := &fileTests[i]
+
+		f, err := Open(tt.file)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		if !reflect.DeepEqual(f.FileHeader, tt.hdr) {
+			t.Errorf("open %s:\n\thave %#v\n\twant %#v\n", tt.file, f.FileHeader, tt.hdr)
+			continue
+		}
+		for i, l := range f.Loads {
+			if i >= len(tt.segments) {
+				break
+			}
+			sh := tt.segments[i]
+			s, ok := l.(*Segment)
+			if sh == nil {
+				if ok {
+					t.Errorf("open %s, section %d: skipping %#v\n", tt.file, i, &s.SegmentHeader)
+				}
+				continue
+			}
+			if !ok {
+				t.Errorf("open %s, section %d: not *Segment\n", tt.file, i)
+				continue
+			}
+			have := &s.SegmentHeader
+			want := sh
+			if !reflect.DeepEqual(have, want) {
+				t.Errorf("open %s, segment %d:\n\thave %#v\n\twant %#v\n", tt.file, i, have, want)
+			}
+		}
+		tn := len(tt.segments)
+		fn := len(f.Loads)
+		if tn != fn {
+			t.Errorf("open %s: len(Loads) = %d, want %d", tt.file, fn, tn)
+		}
+
+		for i, sh := range f.Sections {
+			if i >= len(tt.sections) {
+				break
+			}
+			have := &sh.SectionHeader
+			want := tt.sections[i]
+			if !reflect.DeepEqual(have, want) {
+				t.Errorf("open %s, section %d:\n\thave %#v\n\twant %#v\n", tt.file, i, have, want)
+			}
+		}
+		tn = len(tt.sections)
+		fn = len(f.Sections)
+		if tn != fn {
+			t.Errorf("open %s: len(Sections) = %d, want %d", tt.file, fn, tn)
+		}
+
+	}
+}
+
+func TestOpenFailure(t *testing.T) {
+	filename := "file.go"    // not a Mach-O file
+	_, err := Open(filename) // don't crash
+	if err == nil {
+		t.Errorf("open %s: succeeded unexpectedly", filename)
+	}
+}
diff --git a/libgo/go/debug/macho/macho.go b/libgo/go/debug/macho/macho.go
new file mode 100644
index 000000000..1386f5acf
--- /dev/null
+++ b/libgo/go/debug/macho/macho.go
@@ -0,0 +1,305 @@
+// 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.
+
+// Mach-O header data structures
+// http://developer.apple.com/mac/library/documentation/DeveloperTools/Conceptual/MachORuntime/Reference/reference.html
+
+package macho
+
+import "strconv"
+
+// A FileHeader represents a Mach-O file header.
+type FileHeader struct {
+	Magic  uint32
+	Cpu    Cpu
+	SubCpu uint32
+	Type   Type
+	Ncmd   uint32
+	Cmdsz  uint32
+	Flags  uint32
+}
+
+const (
+	fileHeaderSize32 = 7 * 4
+	fileHeaderSize64 = 8 * 4
+)
+
+const (
+	Magic32 uint32 = 0xfeedface
+	Magic64 uint32 = 0xfeedfacf
+)
+
+// A Type is a Mach-O file type, either an object or an executable.
+type Type uint32
+
+const (
+	TypeObj  Type = 1
+	TypeExec Type = 2
+)
+
+// A Cpu is a Mach-O cpu type.
+type Cpu uint32
+
+const (
+	Cpu386   Cpu = 7
+	CpuAmd64 Cpu = Cpu386 + 1<<24
+)
+
+var cpuStrings = []intName{
+	{uint32(Cpu386), "Cpu386"},
+	{uint32(CpuAmd64), "CpuAmd64"},
+}
+
+func (i Cpu) String() string   { return stringName(uint32(i), cpuStrings, false) }
+func (i Cpu) GoString() string { return stringName(uint32(i), cpuStrings, true) }
+
+// A LoadCmd is a Mach-O load command.
+type LoadCmd uint32
+
+const (
+	LoadCmdSegment    LoadCmd = 1
+	LoadCmdSymtab     LoadCmd = 2
+	LoadCmdThread     LoadCmd = 4
+	LoadCmdUnixThread LoadCmd = 5 // thread+stack
+	LoadCmdDysymtab   LoadCmd = 11
+	LoadCmdDylib      LoadCmd = 12
+	LoadCmdDylinker   LoadCmd = 15
+	LoadCmdSegment64  LoadCmd = 25
+)
+
+var cmdStrings = []intName{
+	{uint32(LoadCmdSegment), "LoadCmdSegment"},
+	{uint32(LoadCmdThread), "LoadCmdThread"},
+	{uint32(LoadCmdUnixThread), "LoadCmdUnixThread"},
+	{uint32(LoadCmdDylib), "LoadCmdDylib"},
+	{uint32(LoadCmdSegment64), "LoadCmdSegment64"},
+}
+
+func (i LoadCmd) String() string   { return stringName(uint32(i), cmdStrings, false) }
+func (i LoadCmd) GoString() string { return stringName(uint32(i), cmdStrings, true) }
+
+// A Segment64 is a 64-bit Mach-O segment load command.
+type Segment64 struct {
+	Cmd     LoadCmd
+	Len     uint32
+	Name    [16]byte
+	Addr    uint64
+	Memsz   uint64
+	Offset  uint64
+	Filesz  uint64
+	Maxprot uint32
+	Prot    uint32
+	Nsect   uint32
+	Flag    uint32
+}
+
+// A Segment32 is a 32-bit Mach-O segment load command.
+type Segment32 struct {
+	Cmd     LoadCmd
+	Len     uint32
+	Name    [16]byte
+	Addr    uint32
+	Memsz   uint32
+	Offset  uint32
+	Filesz  uint32
+	Maxprot uint32
+	Prot    uint32
+	Nsect   uint32
+	Flag    uint32
+}
+
+// A DylibCmd is a Mach-O load dynamic library command.
+type DylibCmd struct {
+	Cmd            LoadCmd
+	Len            uint32
+	Name           uint32
+	Time           uint32
+	CurrentVersion uint32
+	CompatVersion  uint32
+}
+
+// A Section32 is a 32-bit Mach-O section header.
+type Section32 struct {
+	Name     [16]byte
+	Seg      [16]byte
+	Addr     uint32
+	Size     uint32
+	Offset   uint32
+	Align    uint32
+	Reloff   uint32
+	Nreloc   uint32
+	Flags    uint32
+	Reserve1 uint32
+	Reserve2 uint32
+}
+
+// A Section32 is a 64-bit Mach-O section header.
+type Section64 struct {
+	Name     [16]byte
+	Seg      [16]byte
+	Addr     uint64
+	Size     uint64
+	Offset   uint32
+	Align    uint32
+	Reloff   uint32
+	Nreloc   uint32
+	Flags    uint32
+	Reserve1 uint32
+	Reserve2 uint32
+	Reserve3 uint32
+}
+
+// A SymtabCmd is a Mach-O symbol table command.
+type SymtabCmd struct {
+	Cmd     LoadCmd
+	Len     uint32
+	Symoff  uint32
+	Nsyms   uint32
+	Stroff  uint32
+	Strsize uint32
+}
+
+// A DysymtabCmd is a Mach-O dynamic symbol table command.
+type DysymtabCmd struct {
+	Cmd            LoadCmd
+	Len            uint32
+	Ilocalsym      uint32
+	Nlocalsym      uint32
+	Iextdefsym     uint32
+	Nextdefsym     uint32
+	Iundefsym      uint32
+	Nundefsym      uint32
+	Tocoffset      uint32
+	Ntoc           uint32
+	Modtaboff      uint32
+	Nmodtab        uint32
+	Extrefsymoff   uint32
+	Nextrefsyms    uint32
+	Indirectsymoff uint32
+	Nindirectsyms  uint32
+	Extreloff      uint32
+	Nextrel        uint32
+	Locreloff      uint32
+	Nlocrel        uint32
+}
+
+// An Nlist32 is a Mach-O 32-bit symbol table entry.
+type Nlist32 struct {
+	Name  uint32
+	Type  uint8
+	Sect  uint8
+	Desc  uint16
+	Value uint32
+}
+
+// An Nlist64 is a Mach-O 64-bit symbol table entry.
+type Nlist64 struct {
+	Name  uint32
+	Type  uint8
+	Sect  uint8
+	Desc  uint16
+	Value uint64
+}
+
+// A Symbol is a Mach-O 32-bit or 64-bit symbol table entry.
+type Symbol struct {
+	Name  string
+	Type  uint8
+	Sect  uint8
+	Desc  uint16
+	Value uint64
+}
+
+// A Thread is a Mach-O thread state command.
+type Thread struct {
+	Cmd  LoadCmd
+	Len  uint32
+	Type uint32
+	Data []uint32
+}
+
+// Regs386 is the Mach-O 386 register structure.
+type Regs386 struct {
+	AX    uint32
+	BX    uint32
+	CX    uint32
+	DX    uint32
+	DI    uint32
+	SI    uint32
+	BP    uint32
+	SP    uint32
+	SS    uint32
+	FLAGS uint32
+	IP    uint32
+	CS    uint32
+	DS    uint32
+	ES    uint32
+	FS    uint32
+	GS    uint32
+}
+
+// RegsAMD64 is the Mach-O AMD64 register structure.
+type RegsAMD64 struct {
+	AX    uint64
+	BX    uint64
+	CX    uint64
+	DX    uint64
+	DI    uint64
+	SI    uint64
+	BP    uint64
+	SP    uint64
+	R8    uint64
+	R9    uint64
+	R10   uint64
+	R11   uint64
+	R12   uint64
+	R13   uint64
+	R14   uint64
+	R15   uint64
+	IP    uint64
+	FLAGS uint64
+	CS    uint64
+	FS    uint64
+	GS    uint64
+}
+
+type intName struct {
+	i uint32
+	s string
+}
+
+func stringName(i uint32, names []intName, goSyntax bool) string {
+	for _, n := range names {
+		if n.i == i {
+			if goSyntax {
+				return "macho." + n.s
+			}
+			return n.s
+		}
+	}
+	return strconv.Uitoa64(uint64(i))
+}
+
+func flagName(i uint32, names []intName, goSyntax bool) string {
+	s := ""
+	for _, n := range names {
+		if n.i&i == n.i {
+			if len(s) > 0 {
+				s += "+"
+			}
+			if goSyntax {
+				s += "macho."
+			}
+			s += n.s
+			i -= n.i
+		}
+	}
+	if len(s) == 0 {
+		return "0x" + strconv.Uitob64(uint64(i), 16)
+	}
+	if i != 0 {
+		s += "+0x" + strconv.Uitob64(uint64(i), 16)
+	}
+	return s
+}
diff --git a/libgo/go/debug/macho/testdata/gcc-386-darwin-exec b/libgo/go/debug/macho/testdata/gcc-386-darwin-exec
new file mode 100755
index 000000000..03ba1bafa
--- /dev/null
+++ b/libgo/go/debug/macho/testdata/gcc-386-darwin-exec
diff --git a/libgo/go/debug/macho/testdata/gcc-amd64-darwin-exec b/libgo/go/debug/macho/testdata/gcc-amd64-darwin-exec
new file mode 100755
index 000000000..5155a5a26
--- /dev/null
+++ b/libgo/go/debug/macho/testdata/gcc-amd64-darwin-exec
diff --git a/libgo/go/debug/macho/testdata/gcc-amd64-darwin-exec-debug b/libgo/go/debug/macho/testdata/gcc-amd64-darwin-exec-debug
new file mode 100644
index 000000000..a47d3aef7
--- /dev/null
+++ b/libgo/go/debug/macho/testdata/gcc-amd64-darwin-exec-debug
diff --git a/libgo/go/debug/macho/testdata/hello.c b/libgo/go/debug/macho/testdata/hello.c
new file mode 100644
index 000000000..a689d3644
--- /dev/null
+++ b/libgo/go/debug/macho/testdata/hello.c
@@ -0,0 +1,8 @@
+#include <stdio.h>
+
+int
+main(void)
+{
+	printf("hello, world\n");
+	return 0;
+}
diff --git a/libgo/go/debug/pe/file.go b/libgo/go/debug/pe/file.go
new file mode 100644
index 000000000..82c02407b
--- /dev/null
+++ b/libgo/go/debug/pe/file.go
@@ -0,0 +1,309 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package pe implements access to PE (Microsoft Windows Portable Executable) files.
+package pe
+
+import (
+	"debug/dwarf"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+)
+
+// A File represents an open PE file.
+type File struct {
+	FileHeader
+	Sections []*Section
+
+	closer io.Closer
+}
+
+type SectionHeader struct {
+	Name                 string
+	VirtualSize          uint32
+	VirtualAddress       uint32
+	Size                 uint32
+	Offset               uint32
+	PointerToRelocations uint32
+	PointerToLineNumbers uint32
+	NumberOfRelocations  uint16
+	NumberOfLineNumbers  uint16
+	Characteristics      uint32
+}
+
+
+type Section struct {
+	SectionHeader
+
+	// Embed ReaderAt for ReadAt method.
+	// Do not embed SectionReader directly
+	// to avoid having Read and Seek.
+	// If a client wants Read and Seek it must use
+	// Open() to avoid fighting over the seek offset
+	// with other clients.
+	io.ReaderAt
+	sr *io.SectionReader
+}
+
+type ImportDirectory struct {
+	OriginalFirstThunk uint32
+	TimeDateStamp      uint32
+	ForwarderChain     uint32
+	Name               uint32
+	FirstThunk         uint32
+
+	dll string
+	rva []uint32
+}
+
+// Data reads and returns the contents of the PE section.
+func (s *Section) Data() ([]byte, os.Error) {
+	dat := make([]byte, s.sr.Size())
+	n, err := s.sr.ReadAt(dat, 0)
+	return dat[0:n], err
+}
+
+// Open returns a new ReadSeeker reading the PE section.
+func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) }
+
+
+type FormatError struct {
+	off int64
+	msg string
+	val interface{}
+}
+
+func (e *FormatError) String() string {
+	msg := e.msg
+	if e.val != nil {
+		msg += fmt.Sprintf(" '%v'", e.val)
+	}
+	msg += fmt.Sprintf(" in record at byte %#x", e.off)
+	return msg
+}
+
+// Open opens the named file using os.Open and prepares it for use as a PE binary.
+func Open(name string) (*File, os.Error) {
+	f, err := os.Open(name, os.O_RDONLY, 0)
+	if err != nil {
+		return nil, err
+	}
+	ff, err := NewFile(f)
+	if err != nil {
+		f.Close()
+		return nil, err
+	}
+	ff.closer = f
+	return ff, nil
+}
+
+// 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
+	if f.closer != nil {
+		err = f.closer.Close()
+		f.closer = nil
+	}
+	return err
+}
+
+// NewFile creates a new File for acecssing a PE binary in an underlying reader.
+func NewFile(r io.ReaderAt) (*File, os.Error) {
+	f := new(File)
+	sr := io.NewSectionReader(r, 0, 1<<63-1)
+
+	var dosheader [96]byte
+	if _, err := r.ReadAt(dosheader[0:], 0); err != nil {
+		return nil, err
+	}
+	var base int64
+	if dosheader[0] == 'M' && dosheader[1] == 'Z' {
+		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.")
+		}
+		base = int64(dosheader[0x3c]) + 4
+	} else {
+		base = int64(0)
+	}
+	sr.Seek(base, 0)
+	if err := binary.Read(sr, binary.LittleEndian, &f.FileHeader); err != nil {
+		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.")
+	}
+	// get symbol string table
+	sr.Seek(int64(f.FileHeader.PointerToSymbolTable+18*f.FileHeader.NumberOfSymbols), 0)
+	var l uint32
+	if err := binary.Read(sr, binary.LittleEndian, &l); err != nil {
+		return nil, err
+	}
+	ss := make([]byte, l)
+	if _, err := r.ReadAt(ss, int64(f.FileHeader.PointerToSymbolTable+18*f.FileHeader.NumberOfSymbols)); err != nil {
+		return nil, err
+	}
+	sr.Seek(base, 0)
+	binary.Read(sr, binary.LittleEndian, &f.FileHeader)
+	sr.Seek(int64(f.FileHeader.SizeOfOptionalHeader), 1) //Skip OptionalHeader
+	f.Sections = make([]*Section, f.FileHeader.NumberOfSections)
+	for i := 0; i < int(f.FileHeader.NumberOfSections); i++ {
+		sh := new(SectionHeader32)
+		if err := binary.Read(sr, binary.LittleEndian, sh); err != nil {
+			return nil, err
+		}
+		var name string
+		if sh.Name[0] == '\x2F' {
+			si, _ := strconv.Atoi(cstring(sh.Name[1:]))
+			name, _ = getString(ss, si)
+		} else {
+			name = cstring(sh.Name[0:])
+		}
+		s := new(Section)
+		s.SectionHeader = SectionHeader{
+			Name:                 name,
+			VirtualSize:          uint32(sh.VirtualSize),
+			VirtualAddress:       uint32(sh.VirtualAddress),
+			Size:                 uint32(sh.SizeOfRawData),
+			Offset:               uint32(sh.PointerToRawData),
+			PointerToRelocations: uint32(sh.PointerToRelocations),
+			PointerToLineNumbers: uint32(sh.PointerToLineNumbers),
+			NumberOfRelocations:  uint16(sh.NumberOfRelocations),
+			NumberOfLineNumbers:  uint16(sh.NumberOfLineNumbers),
+			Characteristics:      uint32(sh.Characteristics),
+		}
+		s.sr = io.NewSectionReader(r, int64(s.SectionHeader.Offset), int64(s.SectionHeader.Size))
+		s.ReaderAt = s.sr
+		f.Sections[i] = s
+	}
+	return f, nil
+}
+
+func cstring(b []byte) string {
+	var i int
+	for i = 0; i < len(b) && b[i] != 0; i++ {
+	}
+	return string(b[0:i])
+}
+
+// getString extracts a string from symbol string table.
+func getString(section []byte, start int) (string, bool) {
+	if start < 0 || start >= len(section) {
+		return "", false
+	}
+
+	for end := start; end < len(section); end++ {
+		if section[end] == 0 {
+			return string(section[start:end]), true
+		}
+	}
+	return "", false
+}
+
+// Section returns the first section with the given name, or nil if no such
+// section exists.
+func (f *File) Section(name string) *Section {
+	for _, s := range f.Sections {
+		if s.Name == name {
+			return s
+		}
+	}
+	return nil
+}
+
+func (f *File) DWARF() (*dwarf.Data, os.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.
+	var names = [...]string{"abbrev", "info", "str"}
+	var dat [len(names)][]byte
+	for i, name := range names {
+		name = ".debug_" + name
+		s := f.Section(name)
+		if s == nil {
+			continue
+		}
+		b, err := s.Data()
+		if err != nil && uint32(len(b)) < s.Size {
+			return nil, err
+		}
+		dat[i] = b
+	}
+
+	abbrev, info, str := dat[0], dat[1], dat[2]
+	return dwarf.New(abbrev, nil, nil, info, nil, nil, nil, str)
+}
+
+// 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.
+// It does not return weak symbols.
+func (f *File) ImportedSymbols() ([]string, os.Error) {
+	ds := f.Section(".idata")
+	if ds == nil {
+		// not dynamic, so no libraries
+		return nil, nil
+	}
+	d, err := ds.Data()
+	if err != nil {
+		return nil, err
+	}
+	var ida []ImportDirectory
+	for len(d) > 0 {
+		var dt ImportDirectory
+		dt.OriginalFirstThunk = binary.LittleEndian.Uint32(d[0:4])
+		dt.Name = binary.LittleEndian.Uint32(d[12:16])
+		dt.FirstThunk = binary.LittleEndian.Uint32(d[16:20])
+		d = d[20:]
+		if dt.OriginalFirstThunk == 0 {
+			break
+		}
+		ida = append(ida, dt)
+	}
+	for i, _ := range ida {
+		for len(d) > 0 {
+			va := binary.LittleEndian.Uint32(d[0:4])
+			d = d[4:]
+			if va == 0 {
+				break
+			}
+			ida[i].rva = append(ida[i].rva, va)
+		}
+	}
+	for _, _ = range ida {
+		for len(d) > 0 {
+			va := binary.LittleEndian.Uint32(d[0:4])
+			d = d[4:]
+			if va == 0 {
+				break
+			}
+		}
+	}
+	names, _ := ds.Data()
+	var all []string
+	for _, dt := range ida {
+		dt.dll, _ = getString(names, int(dt.Name-ds.VirtualAddress))
+		for _, va := range dt.rva {
+			fn, _ := getString(names, int(va-ds.VirtualAddress+2))
+			all = append(all, fn+":"+dt.dll)
+		}
+	}
+
+	return all, nil
+}
+
+// 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) {
+	// TODO
+	// cgo -dynimport don't use this for windows PE, so just return.
+	return nil, nil
+}
diff --git a/libgo/go/debug/pe/file_test.go b/libgo/go/debug/pe/file_test.go
new file mode 100644
index 000000000..2c5c25b8c
--- /dev/null
+++ b/libgo/go/debug/pe/file_test.go
@@ -0,0 +1,99 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package pe
+
+import (
+	"reflect"
+	"testing"
+)
+
+type fileTest struct {
+	file     string
+	hdr      FileHeader
+	sections []*SectionHeader
+}
+
+var fileTests = []fileTest{
+	{
+		"testdata/gcc-386-mingw-obj",
+		FileHeader{0x014c, 0x000c, 0x0, 0x64a, 0x1e, 0x0, 0x104},
+		[]*SectionHeader{
+			&SectionHeader{".text", 0, 0, 36, 500, 1440, 0, 3, 0, 0x60300020},
+			&SectionHeader{".data", 0, 0, 0, 0, 0, 0, 0, 0, 3224371264},
+			&SectionHeader{".bss", 0, 0, 0, 0, 0, 0, 0, 0, 3224371328},
+			&SectionHeader{".debug_abbrev", 0, 0, 137, 536, 0, 0, 0, 0, 0x42100000},
+			&SectionHeader{".debug_info", 0, 0, 418, 673, 1470, 0, 7, 0, 1108344832},
+			&SectionHeader{".debug_line", 0, 0, 128, 1091, 1540, 0, 1, 0, 1108344832},
+			&SectionHeader{".rdata", 0, 0, 16, 1219, 0, 0, 0, 0, 1076887616},
+			&SectionHeader{".debug_frame", 0, 0, 52, 1235, 1550, 0, 2, 0, 1110441984},
+			&SectionHeader{".debug_loc", 0, 0, 56, 1287, 0, 0, 0, 0, 1108344832},
+			&SectionHeader{".debug_pubnames", 0, 0, 27, 1343, 1570, 0, 1, 0, 1108344832},
+			&SectionHeader{".debug_pubtypes", 0, 0, 38, 1370, 1580, 0, 1, 0, 1108344832},
+			&SectionHeader{".debug_aranges", 0, 0, 32, 1408, 1590, 0, 2, 0, 1108344832},
+		},
+	},
+	{
+		"testdata/gcc-386-mingw-exec",
+		FileHeader{0x014c, 0x000f, 0x4c6a1b60, 0x3c00, 0x282, 0xe0, 0x107},
+		[]*SectionHeader{
+			&SectionHeader{Name: ".text", VirtualSize: 0xcd8, VirtualAddress: 0x1000, Size: 0xe00, Offset: 0x400, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x60500060},
+			&SectionHeader{Name: ".data", VirtualSize: 0x10, VirtualAddress: 0x2000, Size: 0x200, Offset: 0x1200, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0xc0300040},
+			&SectionHeader{Name: ".rdata", VirtualSize: 0x120, VirtualAddress: 0x3000, Size: 0x200, Offset: 0x1400, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x40300040},
+			&SectionHeader{Name: ".bss", VirtualSize: 0xdc, VirtualAddress: 0x4000, Size: 0x0, Offset: 0x0, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0xc0400080},
+			&SectionHeader{Name: ".idata", VirtualSize: 0x3c8, VirtualAddress: 0x5000, Size: 0x400, Offset: 0x1600, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0xc0300040},
+			&SectionHeader{Name: ".CRT", VirtualSize: 0x18, VirtualAddress: 0x6000, Size: 0x200, Offset: 0x1a00, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0xc0300040},
+			&SectionHeader{Name: ".tls", VirtualSize: 0x20, VirtualAddress: 0x7000, Size: 0x200, Offset: 0x1c00, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0xc0300040},
+			&SectionHeader{Name: ".debug_aranges", VirtualSize: 0x20, VirtualAddress: 0x8000, Size: 0x200, Offset: 0x1e00, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x42100000},
+			&SectionHeader{Name: ".debug_pubnames", VirtualSize: 0x51, VirtualAddress: 0x9000, Size: 0x200, Offset: 0x2000, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x42100000},
+			&SectionHeader{Name: ".debug_pubtypes", VirtualSize: 0x91, VirtualAddress: 0xa000, Size: 0x200, Offset: 0x2200, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x42100000},
+			&SectionHeader{Name: ".debug_info", VirtualSize: 0xe22, VirtualAddress: 0xb000, Size: 0x1000, Offset: 0x2400, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x42100000},
+			&SectionHeader{Name: ".debug_abbrev", VirtualSize: 0x157, VirtualAddress: 0xc000, Size: 0x200, Offset: 0x3400, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x42100000},
+			&SectionHeader{Name: ".debug_line", VirtualSize: 0x144, VirtualAddress: 0xd000, Size: 0x200, Offset: 0x3600, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x42100000},
+			&SectionHeader{Name: ".debug_frame", VirtualSize: 0x34, VirtualAddress: 0xe000, Size: 0x200, Offset: 0x3800, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x42300000},
+			&SectionHeader{Name: ".debug_loc", VirtualSize: 0x38, VirtualAddress: 0xf000, Size: 0x200, Offset: 0x3a00, PointerToRelocations: 0x0, PointerToLineNumbers: 0x0, NumberOfRelocations: 0x0, NumberOfLineNumbers: 0x0, Characteristics: 0x42100000},
+		},
+	},
+}
+
+func TestOpen(t *testing.T) {
+	for i := range fileTests {
+		tt := &fileTests[i]
+
+		f, err := Open(tt.file)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		if !reflect.DeepEqual(f.FileHeader, tt.hdr) {
+			t.Errorf("open %s:\n\thave %#v\n\twant %#v\n", tt.file, f.FileHeader, tt.hdr)
+			continue
+		}
+
+		for i, sh := range f.Sections {
+			if i >= len(tt.sections) {
+				break
+			}
+			have := &sh.SectionHeader
+			want := tt.sections[i]
+			if !reflect.DeepEqual(have, want) {
+				t.Errorf("open %s, section %d:\n\thave %#v\n\twant %#v\n", tt.file, i, have, want)
+			}
+		}
+		tn := len(tt.sections)
+		fn := len(f.Sections)
+		if tn != fn {
+			t.Errorf("open %s: len(Sections) = %d, want %d", tt.file, fn, tn)
+		}
+
+	}
+}
+
+func TestOpenFailure(t *testing.T) {
+	filename := "file.go"    // not a PE file
+	_, err := Open(filename) // don't crash
+	if err == nil {
+		t.Errorf("open %s: succeeded unexpectedly", filename)
+	}
+}
diff --git a/libgo/go/debug/pe/pe.go b/libgo/go/debug/pe/pe.go
new file mode 100644
index 000000000..b3dab739a
--- /dev/null
+++ b/libgo/go/debug/pe/pe.go
@@ -0,0 +1,51 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package pe
+
+type FileHeader struct {
+	Machine              uint16
+	NumberOfSections     uint16
+	TimeDateStamp        uint32
+	PointerToSymbolTable uint32
+	NumberOfSymbols      uint32
+	SizeOfOptionalHeader uint16
+	Characteristics      uint16
+}
+
+type SectionHeader32 struct {
+	Name                 [8]uint8
+	VirtualSize          uint32
+	VirtualAddress       uint32
+	SizeOfRawData        uint32
+	PointerToRawData     uint32
+	PointerToRelocations uint32
+	PointerToLineNumbers uint32
+	NumberOfRelocations  uint16
+	NumberOfLineNumbers  uint16
+	Characteristics      uint32
+}
+
+const (
+	IMAGE_FILE_MACHINE_UNKNOWN   = 0x0
+	IMAGE_FILE_MACHINE_AM33      = 0x1d3
+	IMAGE_FILE_MACHINE_AMD64     = 0x8664
+	IMAGE_FILE_MACHINE_ARM       = 0x1c0
+	IMAGE_FILE_MACHINE_EBC       = 0xebc
+	IMAGE_FILE_MACHINE_I386      = 0x14c
+	IMAGE_FILE_MACHINE_IA64      = 0x200
+	IMAGE_FILE_MACHINE_M32R      = 0x9041
+	IMAGE_FILE_MACHINE_MIPS16    = 0x266
+	IMAGE_FILE_MACHINE_MIPSFPU   = 0x366
+	IMAGE_FILE_MACHINE_MIPSFPU16 = 0x466
+	IMAGE_FILE_MACHINE_POWERPC   = 0x1f0
+	IMAGE_FILE_MACHINE_POWERPCFP = 0x1f1
+	IMAGE_FILE_MACHINE_R4000     = 0x166
+	IMAGE_FILE_MACHINE_SH3       = 0x1a2
+	IMAGE_FILE_MACHINE_SH3DSP    = 0x1a3
+	IMAGE_FILE_MACHINE_SH4       = 0x1a6
+	IMAGE_FILE_MACHINE_SH5       = 0x1a8
+	IMAGE_FILE_MACHINE_THUMB     = 0x1c2
+	IMAGE_FILE_MACHINE_WCEMIPSV2 = 0x169
+)
diff --git a/libgo/go/debug/pe/testdata/gcc-386-mingw-exec b/libgo/go/debug/pe/testdata/gcc-386-mingw-exec
new file mode 100644
index 000000000..4b808d043
--- /dev/null
+++ b/libgo/go/debug/pe/testdata/gcc-386-mingw-exec
diff --git a/libgo/go/debug/pe/testdata/gcc-386-mingw-obj b/libgo/go/debug/pe/testdata/gcc-386-mingw-obj
new file mode 100644
index 000000000..0c84d898d
--- /dev/null
+++ b/libgo/go/debug/pe/testdata/gcc-386-mingw-obj
diff --git a/libgo/go/debug/pe/testdata/hello.c b/libgo/go/debug/pe/testdata/hello.c
new file mode 100644
index 000000000..a689d3644
--- /dev/null
+++ b/libgo/go/debug/pe/testdata/hello.c
@@ -0,0 +1,8 @@
+#include <stdio.h>
+
+int
+main(void)
+{
+	printf("hello, world\n");
+	return 0;
+}
diff --git a/libgo/go/debug/proc/proc.go b/libgo/go/debug/proc/proc.go
new file mode 100644
index 000000000..d89649cf8
--- /dev/null
+++ b/libgo/go/debug/proc/proc.go
@@ -0,0 +1,222 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package proc provides a platform-independent interface for
+// tracing and controlling running processes.  It supports
+// multi-threaded processes and provides typical low-level debugging
+// controls such as breakpoints, single stepping, and manipulating
+// memory and registers.
+package proc
+
+// TODO(rsc): Have to import everything that proc_linux.go
+// and proc_darwin.go do, because deps.bash only looks at
+// this file.
+import (
+	_ "container/vector"
+	_ "fmt"
+	_ "io"
+	"os"
+	_ "runtime"
+	"strconv"
+	_ "strings"
+	_ "sync"
+	_ "syscall"
+)
+
+type Word uint64
+
+// A Cause explains why a thread is stopped.
+type Cause interface {
+	String() string
+}
+
+// Regs is a set of named machine registers, including a program
+// counter, link register, and stack pointer.
+//
+// TODO(austin) There's quite a proliferation of methods here.  We
+// could make a Reg interface with Get and Set and make this just PC,
+// Link, SP, Names, and Reg.  We could also put Index in Reg and that
+// makes it easy to get the index of things like the PC (currently
+// there's just no way to know that).  This would also let us include
+// other per-register information like how to print it.
+type Regs interface {
+	// PC returns the value of the program counter.
+	PC() Word
+
+	// SetPC sets the program counter to val.
+	SetPC(val Word) os.Error
+
+	// Link returns the link register, if any.
+	Link() Word
+
+	// SetLink sets the link register to val.
+	SetLink(val Word) os.Error
+
+	// SP returns the value of the stack pointer.
+	SP() Word
+
+	// SetSP sets the stack pointer register to val.
+	SetSP(val Word) os.Error
+
+	// Names returns the names of all of the registers.
+	Names() []string
+
+	// Get returns the value of a register, where i corresponds to
+	// the index of the register's name in the array returned by
+	// Names.
+	Get(i int) Word
+
+	// Set sets the value of a register.
+	Set(i int, val Word) os.Error
+}
+
+// Thread is a thread in the process being traced.
+type Thread interface {
+	// Step steps this thread by a single instruction.  The thread
+	// must be stopped.  If the thread is currently stopped on a
+	// breakpoint, this will step over the breakpoint.
+	//
+	// XXX What if it's stopped because of a signal?
+	Step() os.Error
+
+	// Stopped returns the reason that this thread is stopped.  It
+	// is an error is the thread not stopped.
+	Stopped() (Cause, os.Error)
+
+	// Regs retrieves the current register values from this
+	// thread.  The thread must be stopped.
+	Regs() (Regs, os.Error)
+
+	// Peek reads len(out) bytes from the address addr in this
+	// thread into out.  The thread must be stopped.  It returns
+	// the number of bytes successfully read.  If an error occurs,
+	// such as attempting to read unmapped memory, this count
+	// could be short and an error will be returned.  If this does
+	// encounter unmapped memory, it will read up to the byte
+	// preceding the unmapped area.
+	Peek(addr Word, out []byte) (int, os.Error)
+
+	// Poke writes b to the address addr in this thread.  The
+	// thread must be stopped.  It returns the number of bytes
+	// successfully written.  If an error occurs, such as
+	// attempting to write to unmapped memory, this count could be
+	// short and an error will be returned.  If this does
+	// encounter unmapped memory, it will write up to the byte
+	// preceding the unmapped area.
+	Poke(addr Word, b []byte) (int, os.Error)
+}
+
+// Process is a process being traced.  It consists of a set of
+// threads.  A process can be running, stopped, or terminated.  The
+// process's state extends to all of its threads.
+type Process interface {
+	// Threads returns an array of all threads in this process.
+	Threads() []Thread
+
+	// AddBreakpoint creates a new breakpoint at program counter
+	// pc.  Breakpoints can only be created when the process is
+	// stopped.  It is an error if a breakpoint already exists at
+	// pc.
+	AddBreakpoint(pc Word) os.Error
+
+	// RemoveBreakpoint removes the breakpoint at the program
+	// counter pc.  It is an error if no breakpoint exists at pc.
+	RemoveBreakpoint(pc Word) os.Error
+
+	// Stop stops all running threads in this process before
+	// returning.
+	Stop() os.Error
+
+	// Continue resumes execution of all threads in this process.
+	// Any thread that is stopped on a breakpoint will be stepped
+	// over that breakpoint.  Any thread that is stopped because
+	// of a signal (other than SIGSTOP or SIGTRAP) will receive
+	// the pending signal.
+	Continue() os.Error
+
+	// WaitStop waits until all threads in process p are stopped
+	// as a result of some thread hitting a breakpoint, receiving
+	// a signal, creating a new thread, or exiting.
+	WaitStop() os.Error
+
+	// Detach detaches from this process.  All stopped threads
+	// will be resumed.
+	Detach() os.Error
+}
+
+// Stopped is a stop cause used for threads that are stopped either by
+// user request (e.g., from the Stop method or after single stepping),
+// or that are stopped because some other thread caused the program to
+// stop.
+type Stopped struct{}
+
+func (c Stopped) String() string { return "stopped" }
+
+// Breakpoint is a stop cause resulting from a thread reaching a set
+// breakpoint.
+type Breakpoint Word
+
+// PC returns the program counter that the program is stopped at.
+func (c Breakpoint) PC() Word { return Word(c) }
+
+func (c Breakpoint) String() string {
+	return "breakpoint at 0x" + strconv.Uitob64(uint64(c.PC()), 16)
+}
+
+// Signal is a stop cause resulting from a thread receiving a signal.
+// When the process is continued, the signal will be delivered.
+type Signal string
+
+// Signal returns the signal being delivered to the thread.
+func (c Signal) Name() string { return string(c) }
+
+func (c Signal) String() string { return c.Name() }
+
+// ThreadCreate is a stop cause returned from an existing thread when
+// it creates a new thread.  The new thread exists in a primordial
+// form at this point and will begin executing in earnest when the
+// process is continued.
+type ThreadCreate struct {
+	thread Thread
+}
+
+func (c *ThreadCreate) NewThread() Thread { return c.thread }
+
+func (c *ThreadCreate) String() string { return "thread create" }
+
+// ThreadExit is a stop cause resulting from a thread exiting.  When
+// this cause first arises, the thread will still be in the list of
+// process threads and its registers and memory will still be
+// accessible.
+type ThreadExit struct {
+	exitStatus int
+	signal     string
+}
+
+// Exited returns true if the thread exited normally.
+func (c *ThreadExit) Exited() bool { return c.exitStatus != -1 }
+
+// ExitStatus returns the exit status of the thread if it exited
+// normally or -1 otherwise.
+func (c *ThreadExit) ExitStatus() int { return c.exitStatus }
+
+// Signaled returns true if the thread was terminated by a signal.
+func (c *ThreadExit) Signaled() bool { return c.exitStatus == -1 }
+
+// StopSignal returns the signal that terminated the thread, or "" if
+// it was not terminated by a signal.
+func (c *ThreadExit) StopSignal() string { return c.signal }
+
+func (c *ThreadExit) String() string {
+	res := "thread exited "
+	switch {
+	case c.Exited():
+		res += "with status " + strconv.Itoa(c.ExitStatus())
+	case c.Signaled():
+		res += "from signal " + c.StopSignal()
+	default:
+		res += "from unknown cause"
+	}
+	return res
+}
diff --git a/libgo/go/debug/proc/proc_darwin.go b/libgo/go/debug/proc/proc_darwin.go
new file mode 100644
index 000000000..7caf3a21a
--- /dev/null
+++ b/libgo/go/debug/proc/proc_darwin.go
@@ -0,0 +1,17 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
+
+import "os"
+
+// Process tracing is not supported on OS X yet.
+
+func Attach(pid int) (Process, os.Error) {
+	return nil, os.NewError("debug/proc not implemented on OS X")
+}
+
+func ForkExec(argv0 string, argv []string, envv []string, dir string, fd []*os.File) (Process, os.Error) {
+	return Attach(0)
+}
diff --git a/libgo/go/debug/proc/proc_freebsd.go b/libgo/go/debug/proc/proc_freebsd.go
new file mode 100644
index 000000000..f6474ce80
--- /dev/null
+++ b/libgo/go/debug/proc/proc_freebsd.go
@@ -0,0 +1,17 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
+
+import "os"
+
+// Process tracing is not supported on FreeBSD yet.
+
+func Attach(pid int) (Process, os.Error) {
+	return nil, os.NewError("debug/proc not implemented on FreeBSD")
+}
+
+func ForkExec(argv0 string, argv []string, envv []string, dir string, fd []*os.File) (Process, os.Error) {
+	return Attach(0)
+}
diff --git a/libgo/go/debug/proc/proc_linux.go b/libgo/go/debug/proc/proc_linux.go
new file mode 100644
index 000000000..f0cc43a10
--- /dev/null
+++ b/libgo/go/debug/proc/proc_linux.go
@@ -0,0 +1,1316 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
+
+// TODO(rsc): Imports here after to be in proc.go too in order
+// for deps.bash to get the right answer.
+import (
+	"container/vector"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+)
+
+// This is an implementation of the process tracing interface using
+// Linux's ptrace(2) interface.  The implementation is multi-threaded.
+// Each attached process has an associated monitor thread, and each
+// running attached thread has an associated "wait" thread.  The wait
+// thread calls wait4 on the thread's TID and reports any wait events
+// or errors via "debug events".  The monitor thread consumes these
+// wait events and updates the internally maintained state of each
+// thread.  All ptrace calls must run in the monitor thread, so the
+// monitor executes closures received on the debugReq channel.
+//
+// As ptrace's documentation is somewhat light, this is heavily based
+// on information gleaned from the implementation of ptrace found at
+//   http://lxr.linux.no/linux+v2.6.30/kernel/ptrace.c
+//   http://lxr.linux.no/linux+v2.6.30/arch/x86/kernel/ptrace.c#L854
+// as well as experimentation and examination of gdb's behavior.
+
+const (
+	trace    = false
+	traceIP  = false
+	traceMem = false
+)
+
+/*
+ * Thread state
+ */
+
+// Each thread can be in one of the following set of states.
+// Each state satisfies
+//  isRunning() || isStopped() || isZombie() || isTerminal().
+//
+// Running threads can be sent signals and must be waited on, but they
+// cannot be inspected using ptrace.
+//
+// Stopped threads can be inspected and continued, but cannot be
+// meaningfully waited on.  They can be sent signals, but the signals
+// will be queued until they are running again.
+//
+// Zombie threads cannot be inspected, continued, or sent signals (and
+// therefore they cannot be stopped), but they must be waited on.
+//
+// Terminal threads no longer exist in the OS and thus you can't do
+// anything with them.
+type threadState string
+
+const (
+	running             threadState = "Running"
+	singleStepping      threadState = "SingleStepping" // Transient
+	stopping            threadState = "Stopping"       // Transient
+	stopped             threadState = "Stopped"
+	stoppedBreakpoint   threadState = "StoppedBreakpoint"
+	stoppedSignal       threadState = "StoppedSignal"
+	stoppedThreadCreate threadState = "StoppedThreadCreate"
+	stoppedExiting      threadState = "StoppedExiting"
+	exiting             threadState = "Exiting" // Transient (except main thread)
+	exited              threadState = "Exited"
+	detached            threadState = "Detached"
+)
+
+func (ts threadState) isRunning() bool {
+	return ts == running || ts == singleStepping || ts == stopping
+}
+
+func (ts threadState) isStopped() bool {
+	return ts == stopped || ts == stoppedBreakpoint || ts == stoppedSignal || ts == stoppedThreadCreate || ts == stoppedExiting
+}
+
+func (ts threadState) isZombie() bool { return ts == exiting }
+
+func (ts threadState) isTerminal() bool { return ts == exited || ts == detached }
+
+func (ts threadState) String() string { return string(ts) }
+
+/*
+ * Basic types
+ */
+
+// A breakpoint stores information about a single breakpoint,
+// including its program counter, the overwritten text if the
+// breakpoint is installed.
+type breakpoint struct {
+	pc      uintptr
+	olddata []byte
+}
+
+func (bp *breakpoint) String() string {
+	if bp == nil {
+		return "<nil>"
+	}
+	return fmt.Sprintf("%#x", bp.pc)
+}
+
+// bpinst386 is the breakpoint instruction used on 386 and amd64.
+var bpinst386 = []byte{0xcc}
+
+// A debugEvent represents a reason a thread stopped or a wait error.
+type debugEvent struct {
+	*os.Waitmsg
+	t   *thread
+	err os.Error
+}
+
+// A debugReq is a request to execute a closure in the monitor thread.
+type debugReq struct {
+	f   func() os.Error
+	res chan os.Error
+}
+
+// A transitionHandler specifies a function to be called when a thread
+// changes state and a function to be called when an error occurs in
+// the monitor.  Both run in the monitor thread.  Before the monitor
+// invokes a handler, it removes the handler from the handler queue.
+// The handler should re-add itself if needed.
+type transitionHandler struct {
+	handle func(*thread, threadState, threadState)
+	onErr  func(os.Error)
+}
+
+// A process is a Linux process, which consists of a set of threads.
+// Each running process has one monitor thread, which processes
+// messages from the debugEvents, debugReqs, and stopReq channels and
+// calls transition handlers.
+//
+// To send a message to the monitor thread, first receive from the
+// ready channel.  If the ready channel returns true, the monitor is
+// still running and will accept a message.  If the ready channel
+// returns false, the monitor is not running (the ready channel has
+// been closed), and the reason it is not running will be stored in err.
+type process struct {
+	pid                int
+	threads            map[int]*thread
+	breakpoints        map[uintptr]*breakpoint
+	ready              chan bool
+	debugEvents        chan *debugEvent
+	debugReqs          chan *debugReq
+	stopReq            chan os.Error
+	transitionHandlers vector.Vector
+	err                os.Error
+}
+
+// A thread represents a Linux thread in another process that is being
+// debugged.  Each running thread has an associated goroutine that
+// waits for thread updates and sends them to the process monitor.
+type thread struct {
+	tid  int
+	proc *process
+	// Whether to ignore the next SIGSTOP received by wait.
+	ignoreNextSigstop bool
+
+	// Thread state.  Only modified via setState.
+	state threadState
+	// If state == StoppedBreakpoint
+	breakpoint *breakpoint
+	// If state == StoppedSignal or state == Exited
+	signal int
+	// If state == StoppedThreadCreate
+	newThread *thread
+	// If state == Exited
+	exitStatus int
+}
+
+/*
+ * Errors
+ */
+
+type badState struct {
+	thread  *thread
+	message string
+	state   threadState
+}
+
+func (e *badState) String() string {
+	return fmt.Sprintf("Thread %d %s from state %v", e.thread.tid, e.message, e.state)
+}
+
+type breakpointExistsError Word
+
+func (e breakpointExistsError) String() string {
+	return fmt.Sprintf("breakpoint already exists at PC %#x", e)
+}
+
+type noBreakpointError Word
+
+func (e noBreakpointError) String() string { return fmt.Sprintf("no breakpoint at PC %#x", e) }
+
+type newThreadError struct {
+	*os.Waitmsg
+	wantPid int
+	wantSig int
+}
+
+func (e *newThreadError) String() string {
+	return fmt.Sprintf("newThread wait wanted pid %v and signal %v, got %v and %v", e.Pid, e.StopSignal(), e.wantPid, e.wantSig)
+}
+
+type ProcessExited struct{}
+
+func (p ProcessExited) String() string { return "process exited" }
+
+/*
+ * Ptrace wrappers
+ */
+
+func (t *thread) ptracePeekText(addr uintptr, out []byte) (int, os.Error) {
+	c, err := syscall.PtracePeekText(t.tid, addr, out)
+	if traceMem {
+		fmt.Printf("peek(%#x) => %v, %v\n", addr, out, err)
+	}
+	return c, os.NewSyscallError("ptrace(PEEKTEXT)", err)
+}
+
+func (t *thread) ptracePokeText(addr uintptr, out []byte) (int, os.Error) {
+	c, err := syscall.PtracePokeText(t.tid, addr, out)
+	if traceMem {
+		fmt.Printf("poke(%#x, %v) => %v\n", addr, out, err)
+	}
+	return c, os.NewSyscallError("ptrace(POKETEXT)", err)
+}
+
+func (t *thread) ptraceGetRegs(regs *syscall.PtraceRegs) os.Error {
+	err := syscall.PtraceGetRegs(t.tid, regs)
+	return os.NewSyscallError("ptrace(GETREGS)", err)
+}
+
+func (t *thread) ptraceSetRegs(regs *syscall.PtraceRegs) os.Error {
+	err := syscall.PtraceSetRegs(t.tid, regs)
+	return os.NewSyscallError("ptrace(SETREGS)", err)
+}
+
+func (t *thread) ptraceSetOptions(options int) os.Error {
+	err := syscall.PtraceSetOptions(t.tid, options)
+	return os.NewSyscallError("ptrace(SETOPTIONS)", err)
+}
+
+func (t *thread) ptraceGetEventMsg() (uint, os.Error) {
+	msg, err := syscall.PtraceGetEventMsg(t.tid)
+	return msg, os.NewSyscallError("ptrace(GETEVENTMSG)", err)
+}
+
+func (t *thread) ptraceCont() os.Error {
+	err := syscall.PtraceCont(t.tid, 0)
+	return os.NewSyscallError("ptrace(CONT)", err)
+}
+
+func (t *thread) ptraceContWithSignal(sig int) os.Error {
+	err := syscall.PtraceCont(t.tid, sig)
+	return os.NewSyscallError("ptrace(CONT)", err)
+}
+
+func (t *thread) ptraceStep() os.Error {
+	err := syscall.PtraceSingleStep(t.tid)
+	return os.NewSyscallError("ptrace(SINGLESTEP)", err)
+}
+
+func (t *thread) ptraceDetach() os.Error {
+	err := syscall.PtraceDetach(t.tid)
+	return os.NewSyscallError("ptrace(DETACH)", err)
+}
+
+/*
+ * Logging utilties
+ */
+
+var logLock sync.Mutex
+
+func (t *thread) logTrace(format string, args ...interface{}) {
+	if !trace {
+		return
+	}
+	logLock.Lock()
+	defer logLock.Unlock()
+	fmt.Fprintf(os.Stderr, "Thread %d", t.tid)
+	if traceIP {
+		var regs syscall.PtraceRegs
+		err := t.ptraceGetRegs(&regs)
+		if err == nil {
+			fmt.Fprintf(os.Stderr, "@%x", regs.PC())
+		}
+	}
+	fmt.Fprint(os.Stderr, ": ")
+	fmt.Fprintf(os.Stderr, format, args...)
+	fmt.Fprint(os.Stderr, "\n")
+}
+
+func (t *thread) warn(format string, args ...interface{}) {
+	logLock.Lock()
+	defer logLock.Unlock()
+	fmt.Fprintf(os.Stderr, "Thread %d: WARNING ", t.tid)
+	fmt.Fprintf(os.Stderr, format, args...)
+	fmt.Fprint(os.Stderr, "\n")
+}
+
+func (p *process) logTrace(format string, args ...interface{}) {
+	if !trace {
+		return
+	}
+	logLock.Lock()
+	defer logLock.Unlock()
+	fmt.Fprintf(os.Stderr, "Process %d: ", p.pid)
+	fmt.Fprintf(os.Stderr, format, args...)
+	fmt.Fprint(os.Stderr, "\n")
+}
+
+/*
+ * State utilities
+ */
+
+// someStoppedThread returns a stopped thread from the process.
+// Returns nil if no threads are stopped.
+//
+// Must be called from the monitor thread.
+func (p *process) someStoppedThread() *thread {
+	for _, t := range p.threads {
+		if t.state.isStopped() {
+			return t
+		}
+	}
+	return nil
+}
+
+// someRunningThread returns a running thread from the process.
+// Returns nil if no threads are running.
+//
+// Must be called from the monitor thread.
+func (p *process) someRunningThread() *thread {
+	for _, t := range p.threads {
+		if t.state.isRunning() {
+			return t
+		}
+	}
+	return nil
+}
+
+/*
+ * Breakpoint utilities
+ */
+
+// installBreakpoints adds breakpoints to the attached process.
+//
+// Must be called from the monitor thread.
+func (p *process) installBreakpoints() os.Error {
+	n := 0
+	main := p.someStoppedThread()
+	for _, b := range p.breakpoints {
+		if b.olddata != nil {
+			continue
+		}
+
+		b.olddata = make([]byte, len(bpinst386))
+		_, err := main.ptracePeekText(uintptr(b.pc), b.olddata)
+		if err != nil {
+			b.olddata = nil
+			return err
+		}
+
+		_, err = main.ptracePokeText(uintptr(b.pc), bpinst386)
+		if err != nil {
+			b.olddata = nil
+			return err
+		}
+		n++
+	}
+	if n > 0 {
+		p.logTrace("installed %d/%d breakpoints", n, len(p.breakpoints))
+	}
+
+	return nil
+}
+
+// uninstallBreakpoints removes the installed breakpoints from p.
+//
+// Must be called from the monitor thread.
+func (p *process) uninstallBreakpoints() os.Error {
+	if len(p.threads) == 0 {
+		return nil
+	}
+	n := 0
+	main := p.someStoppedThread()
+	for _, b := range p.breakpoints {
+		if b.olddata == nil {
+			continue
+		}
+
+		_, err := main.ptracePokeText(uintptr(b.pc), b.olddata)
+		if err != nil {
+			return err
+		}
+		b.olddata = nil
+		n++
+	}
+	if n > 0 {
+		p.logTrace("uninstalled %d/%d breakpoints", n, len(p.breakpoints))
+	}
+
+	return nil
+}
+
+/*
+ * Debug event handling
+ */
+
+// wait waits for a wait event from this thread and sends it on the
+// debug events channel for this thread's process.  This should be
+// started in its own goroutine when the attached thread enters a
+// running state.  The goroutine will exit as soon as it sends a debug
+// event.
+func (t *thread) wait() {
+	for {
+		var ev debugEvent
+		ev.t = t
+		t.logTrace("beginning wait")
+		ev.Waitmsg, ev.err = os.Wait(t.tid, syscall.WALL)
+		if ev.err == nil && ev.Pid != t.tid {
+			panic(fmt.Sprint("Wait returned pid ", ev.Pid, " wanted ", t.tid))
+		}
+		if ev.StopSignal() == syscall.SIGSTOP && t.ignoreNextSigstop {
+			// Spurious SIGSTOP.  See Thread.Stop().
+			t.ignoreNextSigstop = false
+			err := t.ptraceCont()
+			if err == nil {
+				continue
+			}
+			// If we failed to continue, just let
+			// the stop go through so we can
+			// update the thread's state.
+		}
+		if !<-t.proc.ready {
+			// The monitor exited
+			break
+		}
+		t.proc.debugEvents <- &ev
+		break
+	}
+}
+
+// setState sets this thread's state, starts a wait thread if
+// necessary, and invokes state transition handlers.
+//
+// Must be called from the monitor thread.
+func (t *thread) setState(newState threadState) {
+	oldState := t.state
+	t.state = newState
+	t.logTrace("state %v -> %v", oldState, newState)
+
+	if !oldState.isRunning() && (newState.isRunning() || newState.isZombie()) {
+		// Start waiting on this thread
+		go t.wait()
+	}
+
+	// Invoke state change handlers
+	handlers := t.proc.transitionHandlers
+	if handlers.Len() == 0 {
+		return
+	}
+
+	t.proc.transitionHandlers = nil
+	for _, h := range handlers {
+		h := h.(*transitionHandler)
+		h.handle(t, oldState, newState)
+	}
+}
+
+// sendSigstop sends a SIGSTOP to this thread.
+func (t *thread) sendSigstop() os.Error {
+	t.logTrace("sending SIGSTOP")
+	err := syscall.Tgkill(t.proc.pid, t.tid, syscall.SIGSTOP)
+	return os.NewSyscallError("tgkill", err)
+}
+
+// stopAsync sends SIGSTOP to all threads in state 'running'.
+//
+// Must be called from the monitor thread.
+func (p *process) stopAsync() os.Error {
+	for _, t := range p.threads {
+		if t.state == running {
+			err := t.sendSigstop()
+			if err != nil {
+				return err
+			}
+			t.setState(stopping)
+		}
+	}
+	return nil
+}
+
+// doTrap handles SIGTRAP debug events with a cause of 0.  These can
+// be caused either by an installed breakpoint, a breakpoint in the
+// program text, or by single stepping.
+//
+// TODO(austin) I think we also get this on an execve syscall.
+func (ev *debugEvent) doTrap() (threadState, os.Error) {
+	t := ev.t
+
+	if t.state == singleStepping {
+		return stopped, nil
+	}
+
+	// Hit a breakpoint.  Linux leaves the program counter after
+	// the breakpoint.  If this is an installed breakpoint, we
+	// need to back the PC up to the breakpoint PC.
+	var regs syscall.PtraceRegs
+	err := t.ptraceGetRegs(&regs)
+	if err != nil {
+		return stopped, err
+	}
+
+	b, ok := t.proc.breakpoints[uintptr(regs.PC())-uintptr(len(bpinst386))]
+	if !ok {
+		// We must have hit a breakpoint that was actually in
+		// the program.  Leave the IP where it is so we don't
+		// re-execute the breakpoint instruction.  Expose the
+		// fact that we stopped with a SIGTRAP.
+		return stoppedSignal, nil
+	}
+
+	t.breakpoint = b
+	t.logTrace("at breakpoint %v, backing up PC from %#x", b, regs.PC())
+
+	regs.SetPC(uint64(b.pc))
+	err = t.ptraceSetRegs(&regs)
+	if err != nil {
+		return stopped, err
+	}
+	return stoppedBreakpoint, nil
+}
+
+// doPtraceClone handles SIGTRAP debug events with a PTRACE_EVENT_CLONE
+// cause.  It initializes the new thread, adds it to the process, and
+// returns the appropriate thread state for the existing thread.
+func (ev *debugEvent) doPtraceClone() (threadState, os.Error) {
+	t := ev.t
+
+	// Get the TID of the new thread
+	tid, err := t.ptraceGetEventMsg()
+	if err != nil {
+		return stopped, err
+	}
+
+	nt, err := t.proc.newThread(int(tid), syscall.SIGSTOP, true)
+	if err != nil {
+		return stopped, err
+	}
+
+	// Remember the thread
+	t.newThread = nt
+
+	return stoppedThreadCreate, nil
+}
+
+// doPtraceExit handles SIGTRAP debug events with a PTRACE_EVENT_EXIT
+// cause.  It sets up the thread's state, but does not remove it from
+// the process.  A later WIFEXITED debug event will remove it from the
+// process.
+func (ev *debugEvent) doPtraceExit() (threadState, os.Error) {
+	t := ev.t
+
+	// Get exit status
+	exitStatus, err := t.ptraceGetEventMsg()
+	if err != nil {
+		return stopped, err
+	}
+	ws := syscall.WaitStatus(exitStatus)
+	t.logTrace("exited with %v", ws)
+	switch {
+	case ws.Exited():
+		t.exitStatus = ws.ExitStatus()
+	case ws.Signaled():
+		t.signal = ws.Signal()
+	}
+
+	// We still need to continue this thread and wait on this
+	// thread's WIFEXITED event.  We'll delete it then.
+	return stoppedExiting, nil
+}
+
+// process handles a debug event.  It modifies any thread or process
+// state as necessary, uninstalls breakpoints if necessary, and stops
+// any running threads.
+func (ev *debugEvent) process() os.Error {
+	if ev.err != nil {
+		return ev.err
+	}
+
+	t := ev.t
+	t.exitStatus = -1
+	t.signal = -1
+
+	// Decode wait status.
+	var state threadState
+	switch {
+	case ev.Stopped():
+		state = stoppedSignal
+		t.signal = ev.StopSignal()
+		t.logTrace("stopped with %v", ev)
+		if ev.StopSignal() == syscall.SIGTRAP {
+			// What caused the debug trap?
+			var err os.Error
+			switch cause := ev.TrapCause(); cause {
+			case 0:
+				// Breakpoint or single stepping
+				state, err = ev.doTrap()
+
+			case syscall.PTRACE_EVENT_CLONE:
+				state, err = ev.doPtraceClone()
+
+			case syscall.PTRACE_EVENT_EXIT:
+				state, err = ev.doPtraceExit()
+
+			default:
+				t.warn("Unknown trap cause %d", cause)
+			}
+
+			if err != nil {
+				t.setState(stopped)
+				t.warn("failed to handle trap %v: %v", ev, err)
+			}
+		}
+
+	case ev.Exited():
+		state = exited
+		t.proc.threads[t.tid] = nil, false
+		t.logTrace("exited %v", ev)
+		// We should have gotten the exit status in
+		// PTRACE_EVENT_EXIT, but just in case.
+		t.exitStatus = ev.ExitStatus()
+
+	case ev.Signaled():
+		state = exited
+		t.proc.threads[t.tid] = nil, false
+		t.logTrace("signaled %v", ev)
+		// Again, this should be redundant.
+		t.signal = ev.Signal()
+
+	default:
+		panic(fmt.Sprintf("Unexpected wait status %v", ev.Waitmsg))
+	}
+
+	// If we sent a SIGSTOP to the thread (indicated by state
+	// Stopping), we might have raced with a different type of
+	// stop.  If we didn't get the stop we expected, then the
+	// SIGSTOP we sent is now queued up, so we should ignore the
+	// next one we get.
+	if t.state == stopping && ev.StopSignal() != syscall.SIGSTOP {
+		t.ignoreNextSigstop = true
+	}
+
+	// TODO(austin) If we're in state stopping and get a SIGSTOP,
+	// set state stopped instead of stoppedSignal.
+
+	t.setState(state)
+
+	if t.proc.someRunningThread() == nil {
+		// Nothing is running, uninstall breakpoints
+		return t.proc.uninstallBreakpoints()
+	}
+	// Stop any other running threads
+	return t.proc.stopAsync()
+}
+
+// onStop adds a handler for state transitions from running to
+// non-running states.  The handler will be called from the monitor
+// thread.
+//
+// Must be called from the monitor thread.
+func (t *thread) onStop(handle func(), onErr func(os.Error)) {
+	// TODO(austin) This is rather inefficient for things like
+	// stepping all threads during a continue.  Maybe move
+	// transitionHandlers to the thread, or have both per-thread
+	// and per-process transition handlers.
+	h := &transitionHandler{nil, onErr}
+	h.handle = func(st *thread, old, new threadState) {
+		if t == st && old.isRunning() && !new.isRunning() {
+			handle()
+		} else {
+			t.proc.transitionHandlers.Push(h)
+		}
+	}
+	t.proc.transitionHandlers.Push(h)
+}
+
+/*
+ * Event monitor
+ */
+
+// monitor handles debug events and debug requests for p, exiting when
+// there are no threads left in p.
+func (p *process) monitor() {
+	var err os.Error
+
+	// Linux requires that all ptrace calls come from the thread
+	// that originally attached.  Prevent the Go scheduler from
+	// migrating us to other OS threads.
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	hadThreads := false
+	for err == nil {
+		p.ready <- true
+		select {
+		case event := <-p.debugEvents:
+			err = event.process()
+
+		case req := <-p.debugReqs:
+			req.res <- req.f()
+
+		case err = <-p.stopReq:
+			break
+		}
+
+		if len(p.threads) == 0 {
+			if err == nil && hadThreads {
+				p.logTrace("no more threads; monitor exiting")
+				err = ProcessExited{}
+			}
+		} else {
+			hadThreads = true
+		}
+	}
+
+	// Abort waiting handlers
+	// TODO(austin) How do I stop the wait threads?
+	for _, h := range p.transitionHandlers {
+		h := h.(*transitionHandler)
+		h.onErr(err)
+	}
+
+	// Indicate that the monitor cannot receive any more messages
+	p.err = err
+	close(p.ready)
+}
+
+// do executes f in the monitor thread (and, thus, atomically with
+// respect to thread state changes).  f must not block.
+//
+// Must NOT be called from the monitor thread.
+func (p *process) do(f func() os.Error) os.Error {
+	if !<-p.ready {
+		return p.err
+	}
+	req := &debugReq{f, make(chan os.Error)}
+	p.debugReqs <- req
+	return <-req.res
+}
+
+// stopMonitor stops the monitor with the given error.  If the monitor
+// is already stopped, does nothing.
+func (p *process) stopMonitor(err os.Error) {
+	if err == nil {
+		panic("cannot stop the monitor with no error")
+	}
+	if <-p.ready {
+		p.stopReq <- err
+	}
+}
+
+/*
+ * Public thread interface
+ */
+
+func (t *thread) Regs() (Regs, os.Error) {
+	var regs syscall.PtraceRegs
+
+	err := t.proc.do(func() os.Error {
+		if !t.state.isStopped() {
+			return &badState{t, "cannot get registers", t.state}
+		}
+		return t.ptraceGetRegs(&regs)
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	setter := func(r *syscall.PtraceRegs) os.Error {
+		return t.proc.do(func() os.Error {
+			if !t.state.isStopped() {
+				return &badState{t, "cannot get registers", t.state}
+			}
+			return t.ptraceSetRegs(r)
+		})
+	}
+	return newRegs(&regs, setter), nil
+}
+
+func (t *thread) Peek(addr Word, out []byte) (int, os.Error) {
+	var c int
+
+	err := t.proc.do(func() os.Error {
+		if !t.state.isStopped() {
+			return &badState{t, "cannot peek text", t.state}
+		}
+
+		var err os.Error
+		c, err = t.ptracePeekText(uintptr(addr), out)
+		return err
+	})
+
+	return c, err
+}
+
+func (t *thread) Poke(addr Word, out []byte) (int, os.Error) {
+	var c int
+
+	err := t.proc.do(func() os.Error {
+		if !t.state.isStopped() {
+			return &badState{t, "cannot poke text", t.state}
+		}
+
+		var err os.Error
+		c, err = t.ptracePokeText(uintptr(addr), out)
+		return err
+	})
+
+	return c, err
+}
+
+// stepAsync starts this thread single stepping.  When the single step
+// is complete, it will send nil on the given channel.  If an error
+// occurs while setting up the single step, it returns that error.  If
+// an error occurs while waiting for the single step to complete, it
+// sends that error on the channel.
+func (t *thread) stepAsync(ready chan os.Error) os.Error {
+	if err := t.ptraceStep(); err != nil {
+		return err
+	}
+	t.setState(singleStepping)
+	t.onStop(func() { ready <- nil },
+		func(err os.Error) { ready <- err })
+	return nil
+}
+
+func (t *thread) Step() os.Error {
+	t.logTrace("Step {")
+	defer t.logTrace("}")
+
+	ready := make(chan os.Error)
+
+	err := t.proc.do(func() os.Error {
+		if !t.state.isStopped() {
+			return &badState{t, "cannot single step", t.state}
+		}
+		return t.stepAsync(ready)
+	})
+	if err != nil {
+		return err
+	}
+
+	err = <-ready
+	return err
+}
+
+// TODO(austin) We should probably get this via C's strsignal.
+var sigNames = [...]string{
+	"SIGEXIT", "SIGHUP", "SIGINT", "SIGQUIT", "SIGILL",
+	"SIGTRAP", "SIGABRT", "SIGBUS", "SIGFPE", "SIGKILL",
+	"SIGUSR1", "SIGSEGV", "SIGUSR2", "SIGPIPE", "SIGALRM",
+	"SIGTERM", "SIGSTKFLT", "SIGCHLD", "SIGCONT", "SIGSTOP",
+	"SIGTSTP", "SIGTTIN", "SIGTTOU", "SIGURG", "SIGXCPU",
+	"SIGXFSZ", "SIGVTALRM", "SIGPROF", "SIGWINCH", "SIGPOLL",
+	"SIGPWR", "SIGSYS",
+}
+
+// sigName returns the symbolic name for the given signal number.  If
+// the signal number is invalid, returns "<invalid>".
+func sigName(signal int) string {
+	if signal < 0 || signal >= len(sigNames) {
+		return "<invalid>"
+	}
+	return sigNames[signal]
+}
+
+func (t *thread) Stopped() (Cause, os.Error) {
+	var c Cause
+	err := t.proc.do(func() os.Error {
+		switch t.state {
+		case stopped:
+			c = Stopped{}
+
+		case stoppedBreakpoint:
+			c = Breakpoint(t.breakpoint.pc)
+
+		case stoppedSignal:
+			c = Signal(sigName(t.signal))
+
+		case stoppedThreadCreate:
+			c = &ThreadCreate{t.newThread}
+
+		case stoppedExiting, exiting, exited:
+			if t.signal == -1 {
+				c = &ThreadExit{t.exitStatus, ""}
+			} else {
+				c = &ThreadExit{t.exitStatus, sigName(t.signal)}
+			}
+
+		default:
+			return &badState{t, "cannot get stop cause", t.state}
+		}
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return c, nil
+}
+
+func (p *process) Threads() []Thread {
+	var res []Thread
+
+	p.do(func() os.Error {
+		res = make([]Thread, len(p.threads))
+		i := 0
+		for _, t := range p.threads {
+			// Exclude zombie threads.
+			st := t.state
+			if st == exiting || st == exited || st == detached {
+				continue
+			}
+
+			res[i] = t
+			i++
+		}
+		res = res[0:i]
+		return nil
+	})
+	return res
+}
+
+func (p *process) AddBreakpoint(pc Word) os.Error {
+	return p.do(func() os.Error {
+		if t := p.someRunningThread(); t != nil {
+			return &badState{t, "cannot add breakpoint", t.state}
+		}
+		if _, ok := p.breakpoints[uintptr(pc)]; ok {
+			return breakpointExistsError(pc)
+		}
+		p.breakpoints[uintptr(pc)] = &breakpoint{pc: uintptr(pc)}
+		return nil
+	})
+}
+
+func (p *process) RemoveBreakpoint(pc Word) os.Error {
+	return p.do(func() os.Error {
+		if t := p.someRunningThread(); t != nil {
+			return &badState{t, "cannot remove breakpoint", t.state}
+		}
+		if _, ok := p.breakpoints[uintptr(pc)]; !ok {
+			return noBreakpointError(pc)
+		}
+		p.breakpoints[uintptr(pc)] = nil, false
+		return nil
+	})
+}
+
+func (p *process) Continue() os.Error {
+	// Single step any threads that are stopped at breakpoints so
+	// we can reinstall breakpoints.
+	var ready chan os.Error
+	count := 0
+
+	err := p.do(func() os.Error {
+		// We make the ready channel big enough to hold all
+		// ready message so we don't jam up the monitor if we
+		// stop listening (e.g., if there's an error).
+		ready = make(chan os.Error, len(p.threads))
+
+		for _, t := range p.threads {
+			if !t.state.isStopped() {
+				continue
+			}
+
+			// We use the breakpoint map directly here
+			// instead of checking the stop cause because
+			// it could have been stopped at a breakpoint
+			// for some other reason, or the breakpoint
+			// could have been added since it was stopped.
+			var regs syscall.PtraceRegs
+			err := t.ptraceGetRegs(&regs)
+			if err != nil {
+				return err
+			}
+			if b, ok := p.breakpoints[uintptr(regs.PC())]; ok {
+				t.logTrace("stepping over breakpoint %v", b)
+				if err := t.stepAsync(ready); err != nil {
+					return err
+				}
+				count++
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		p.stopMonitor(err)
+		return err
+	}
+
+	// Wait for single stepping threads
+	for count > 0 {
+		err = <-ready
+		if err != nil {
+			p.stopMonitor(err)
+			return err
+		}
+		count--
+	}
+
+	// Continue all threads
+	err = p.do(func() os.Error {
+		if err := p.installBreakpoints(); err != nil {
+			return err
+		}
+
+		for _, t := range p.threads {
+			var err os.Error
+			switch {
+			case !t.state.isStopped():
+				continue
+
+			case t.state == stoppedSignal && t.signal != syscall.SIGSTOP && t.signal != syscall.SIGTRAP:
+				t.logTrace("continuing with signal %d", t.signal)
+				err = t.ptraceContWithSignal(t.signal)
+
+			default:
+				t.logTrace("continuing")
+				err = t.ptraceCont()
+			}
+			if err != nil {
+				return err
+			}
+			if t.state == stoppedExiting {
+				t.setState(exiting)
+			} else {
+				t.setState(running)
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		// TODO(austin) Do we need to stop the monitor with
+		// this error atomically with the do-routine above?
+		p.stopMonitor(err)
+		return err
+	}
+
+	return nil
+}
+
+func (p *process) WaitStop() os.Error {
+	// We need a non-blocking ready channel for the case where all
+	// threads are already stopped.
+	ready := make(chan os.Error, 1)
+
+	err := p.do(func() os.Error {
+		// Are all of the threads already stopped?
+		if p.someRunningThread() == nil {
+			ready <- nil
+			return nil
+		}
+
+		// Monitor state transitions
+		h := &transitionHandler{}
+		h.handle = func(st *thread, old, new threadState) {
+			if !new.isRunning() {
+				if p.someRunningThread() == nil {
+					ready <- nil
+					return
+				}
+			}
+			p.transitionHandlers.Push(h)
+		}
+		h.onErr = func(err os.Error) { ready <- err }
+		p.transitionHandlers.Push(h)
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	return <-ready
+}
+
+func (p *process) Stop() os.Error {
+	err := p.do(func() os.Error { return p.stopAsync() })
+	if err != nil {
+		return err
+	}
+
+	return p.WaitStop()
+}
+
+func (p *process) Detach() os.Error {
+	if err := p.Stop(); err != nil {
+		return err
+	}
+
+	err := p.do(func() os.Error {
+		if err := p.uninstallBreakpoints(); err != nil {
+			return err
+		}
+
+		for pid, t := range p.threads {
+			if t.state.isStopped() {
+				// We can't detach from zombies.
+				if err := t.ptraceDetach(); err != nil {
+					return err
+				}
+			}
+			t.setState(detached)
+			p.threads[pid] = nil, false
+		}
+		return nil
+	})
+	// TODO(austin) Wait for monitor thread to exit?
+	return err
+}
+
+// newThread creates a new thread object and waits for its initial
+// signal.  If cloned is true, this thread was cloned from a thread we
+// are already attached to.
+//
+// Must be run from the monitor thread.
+func (p *process) newThread(tid int, signal int, cloned bool) (*thread, os.Error) {
+	t := &thread{tid: tid, proc: p, state: stopped}
+
+	// Get the signal from the thread
+	// TODO(austin) Thread might already be stopped if we're attaching.
+	w, err := os.Wait(tid, syscall.WALL)
+	if err != nil {
+		return nil, err
+	}
+	if w.Pid != tid || w.StopSignal() != signal {
+		return nil, &newThreadError{w, tid, signal}
+	}
+
+	if !cloned {
+		err = t.ptraceSetOptions(syscall.PTRACE_O_TRACECLONE | syscall.PTRACE_O_TRACEEXIT)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	p.threads[tid] = t
+
+	return t, nil
+}
+
+// attachThread attaches a running thread to the process.
+//
+// Must NOT be run from the monitor thread.
+func (p *process) attachThread(tid int) (*thread, os.Error) {
+	p.logTrace("attaching to thread %d", tid)
+	var thr *thread
+	err := p.do(func() os.Error {
+		errno := syscall.PtraceAttach(tid)
+		if errno != 0 {
+			return os.NewSyscallError("ptrace(ATTACH)", errno)
+		}
+
+		var err os.Error
+		thr, err = p.newThread(tid, syscall.SIGSTOP, false)
+		return err
+	})
+	return thr, err
+}
+
+// attachAllThreads attaches to all threads in a process.
+func (p *process) attachAllThreads() os.Error {
+	taskPath := "/proc/" + strconv.Itoa(p.pid) + "/task"
+	taskDir, err := os.Open(taskPath, os.O_RDONLY, 0)
+	if err != nil {
+		return err
+	}
+	defer taskDir.Close()
+
+	// We stop threads as we attach to them; however, because new
+	// threads can appear while we're looping over all of them, we
+	// have to repeatly scan until we know we're attached to all
+	// of them.
+	for again := true; again; {
+		again = false
+
+		tids, err := taskDir.Readdirnames(-1)
+		if err != nil {
+			return err
+		}
+
+		for _, tidStr := range tids {
+			tid, err := strconv.Atoi(tidStr)
+			if err != nil {
+				return err
+			}
+			if _, ok := p.threads[tid]; ok {
+				continue
+			}
+
+			_, err = p.attachThread(tid)
+			if err != nil {
+				// There could have been a race, or
+				// this process could be a zobmie.
+				statFile, err2 := ioutil.ReadFile(taskPath + "/" + tidStr + "/stat")
+				if err2 != nil {
+					switch err2 := err2.(type) {
+					case *os.PathError:
+						if err2.Error == os.ENOENT {
+							// Raced with thread exit
+							p.logTrace("raced with thread %d exit", tid)
+							continue
+						}
+					}
+					// Return the original error
+					return err
+				}
+
+				statParts := strings.Split(string(statFile), " ", 4)
+				if len(statParts) > 2 && statParts[2] == "Z" {
+					// tid is a zombie
+					p.logTrace("thread %d is a zombie", tid)
+					continue
+				}
+
+				// Return the original error
+				return err
+			}
+			again = true
+		}
+	}
+
+	return nil
+}
+
+// newProcess creates a new process object and starts its monitor thread.
+func newProcess(pid int) *process {
+	p := &process{
+		pid:         pid,
+		threads:     make(map[int]*thread),
+		breakpoints: make(map[uintptr]*breakpoint),
+		ready:       make(chan bool, 1),
+		debugEvents: make(chan *debugEvent),
+		debugReqs:   make(chan *debugReq),
+		stopReq:     make(chan os.Error),
+	}
+
+	go p.monitor()
+
+	return p
+}
+
+// Attach attaches to process pid and stops all of its threads.
+func Attach(pid int) (Process, os.Error) {
+	p := newProcess(pid)
+
+	// Attach to all threads
+	err := p.attachAllThreads()
+	if err != nil {
+		p.Detach()
+		// TODO(austin) Detach stopped the monitor already
+		//p.stopMonitor(err);
+		return nil, err
+	}
+
+	return p, nil
+}
+
+// ForkExec forks the current process and execs argv0, stopping the
+// new process after the exec syscall.  See os.ForkExec for additional
+// details.
+func ForkExec(argv0 string, argv []string, envv []string, dir string, fd []*os.File) (Process, os.Error) {
+	p := newProcess(-1)
+
+	// Create array of integer (system) fds.
+	intfd := make([]int, len(fd))
+	for i, f := range fd {
+		if f == nil {
+			intfd[i] = -1
+		} else {
+			intfd[i] = f.Fd()
+		}
+	}
+
+	// Fork from the monitor thread so we get the right tracer pid.
+	err := p.do(func() os.Error {
+		pid, errno := syscall.PtraceForkExec(argv0, argv, envv, dir, intfd)
+		if errno != 0 {
+			return &os.PathError{"fork/exec", argv0, os.Errno(errno)}
+		}
+		p.pid = pid
+
+		// The process will raise SIGTRAP when it reaches execve.
+		_, err := p.newThread(pid, syscall.SIGTRAP, false)
+		return err
+	})
+	if err != nil {
+		p.stopMonitor(err)
+		return nil, err
+	}
+
+	return p, nil
+}
diff --git a/libgo/go/debug/proc/proc_rtems.go b/libgo/go/debug/proc/proc_rtems.go
new file mode 100644
index 000000000..5311a63ba
--- /dev/null
+++ b/libgo/go/debug/proc/proc_rtems.go
@@ -0,0 +1,17 @@
+// 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 proc
+
+import "os"
+
+// Process tracing is not supported on RTEMS yet.
+
+func Attach(pid int) (Process, os.Error) {
+	return nil, os.NewError("debug/proc not implemented on RTEMS")
+}
+
+func ForkExec(argv0 string, argv []string, envv []string, dir string, fd []*os.File) (Process, os.Error) {
+	return Attach(0)
+}
diff --git a/libgo/go/debug/proc/proc_solaris.go b/libgo/go/debug/proc/proc_solaris.go
new file mode 100644
index 000000000..a72c59237
--- /dev/null
+++ b/libgo/go/debug/proc/proc_solaris.go
@@ -0,0 +1,17 @@
+// 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 proc
+
+import "os"
+
+// Process tracing is not supported on Solaris yet.
+
+func Attach(pid int) (Process, os.Error) {
+	return nil, os.NewError("debug/proc not implemented on Solaris")
+}
+
+func ForkExec(argv0 string, argv []string, envv []string, dir string, fd []*os.File) (Process, os.Error) {
+	return Attach(0)
+}
diff --git a/libgo/go/debug/proc/proc_windows.go b/libgo/go/debug/proc/proc_windows.go
new file mode 100644
index 000000000..dc22faef8
--- /dev/null
+++ b/libgo/go/debug/proc/proc_windows.go
@@ -0,0 +1,17 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
+
+import "os"
+
+// Process tracing is not supported on windows yet.
+
+func Attach(pid int) (Process, os.Error) {
+	return nil, os.NewError("debug/proc not implemented on windows")
+}
+
+func ForkExec(argv0 string, argv []string, envv []string, dir string, fd []*os.File) (Process, os.Error) {
+	return Attach(0)
+}
diff --git a/libgo/go/debug/proc/ptrace-nptl.txt b/libgo/go/debug/proc/ptrace-nptl.txt
new file mode 100644
index 000000000..62cbf7700
--- /dev/null
+++ b/libgo/go/debug/proc/ptrace-nptl.txt
@@ -0,0 +1,132 @@
+// 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.
+
+ptrace and NTPL, the missing manpage
+
+== Signals ==
+
+A signal sent to a ptrace'd process or thread causes only the thread
+that receives it to stop and report to the attached process.
+
+Use tgkill to target a signal (for example, SIGSTOP) at a particular
+thread.  If you use kill, the signal could be delivered to another
+thread in the same process.
+
+Note that SIGSTOP differs from its usual behavior when a process is
+being traced.  Usually, a SIGSTOP sent to any thread in a thread group
+will stop all threads in the thread group.  When a thread is traced,
+however, a SIGSTOP affects only the receiving thread (and any other
+threads in the thread group that are not traced).
+
+SIGKILL behaves like it does for non-traced processes.  It affects all
+threads in the process and terminates them without the WSTOPSIG event
+generated by other signals.  However, if PTRACE_O_TRACEEXIT is set,
+the attached process will still receive PTRACE_EVENT_EXIT events
+before receiving WIFSIGNALED events.
+
+See "Following thread death" for a caveat regarding signal delivery to
+zombie threads.
+
+== Waiting on threads ==
+
+Cloned threads in ptrace'd processes are treated similarly to cloned
+threads in your own process.  Thus, you must use the __WALL option in
+order to receive notifications from threads created by the child
+process.  Similarly, the __WCLONE option will wait only on
+notifications from threads created by the child process and *not* on
+notifications from the initial child thread.
+
+Even when waiting on a specific thread's PID using waitpid or similar,
+__WALL or __WCLONE is necessary or waitpid will return ECHILD.
+
+== Attaching to existing threads ==
+
+libthread_db (which gdb uses), attaches to existing threads by pulling
+the pthread data structures out of the traced process.  The much
+easier way is to traverse the /proc/PID/task directory, though it's
+unclear how the semantics of these two approaches differ.
+
+Unfortunately, if the main thread has exited (but the overall process
+has not), it sticks around as a zombie process.  This zombie will
+appear in the /proc/PID/task directory, but trying to attach to it
+will yield EPERM.  In this case, the third field of the
+/proc/PID/task/PID/stat file will be "Z".  Attempting to open the stat
+file is also a convenient way to detect races between listing the task
+directory and the thread exiting.  Coincidentally, gdb will simply
+fail to attach to a process whose main thread is a zombie.
+
+Because new threads may be created while the debugger is in the
+process of attaching to existing threads, the debugger must repeatedly
+re-list the task directory until it has attached to (and thus stopped)
+every thread listed.
+
+In order to follow new threads created by existing threads,
+PTRACE_O_TRACECLONE must be set on each thread attached to.
+
+== Following new threads ==
+
+With the child process stopped, use PTRACE_SETOPTIONS to set the
+PTRACE_O_TRACECLONE option.  This option is per-thread, and thus must
+be set on each existing thread individually.  When an existing thread
+with PTRACE_O_TRACECLONE set spawns a new thread, the existing thread
+will stop with (SIGTRAP | PTRACE_EVENT_CLONE << 8) and the PID of the
+new thread can be retrieved with PTRACE_GETEVENTMSG on the creating
+thread.  At this time, the new thread will exist, but will initially
+be stopped with a SIGSTOP.  The new thread will automatically be
+traced and will inherit the PTRACE_O_TRACECLONE option from its
+parent.  The attached process should wait on the new thread to receive
+the SIGSTOP notification.
+
+When using waitpid(-1, ...), don't rely on the parent thread reporting
+a SIGTRAP before receiving the SIGSTOP from the new child thread.
+
+Without PTRACE_O_TRACECLONE, newly cloned threads will not be
+ptrace'd.  As a result, signals received by new threads will be
+handled in the usual way, which may affect the parent and in turn
+appear to the attached process, but attributed to the parent (possibly
+in unexpected ways).
+
+== Following thread death ==
+
+If any thread with the PTRACE_O_TRACEEXIT option set exits (either by
+returning or pthread_exit'ing), the tracing process will receive an
+immediate PTRACE_EVENT_EXIT.  At this point, the thread will still
+exist.  The exit status, encoded as for wait, can be queried using
+PTRACE_GETEVENTMSG on the exiting thread's PID.  The thread should be
+continued so it can actually exit, after which its wait behavior is
+the same as for a thread without the PTRACE_O_TRACEEXIT option.
+
+If a non-main thread exits (either by returning or pthread_exit'ing),
+its corresponding process will also exit, producing a WIFEXITED event
+(after the process is continued from a possible PTRACE_EVENT_EXIT
+event).  It is *not* necessary for another thread to ptrace_join for
+this to happen.
+
+If the main thread exits by returning, then all threads will exit,
+first generating a PTRACE_EVENT_EXIT event for each thread if
+appropriate, then producing a WIFEXITED event for each thread.
+
+If the main thread exits using pthread_exit, then it enters a
+non-waitable zombie state.  It will still produce an immediate
+PTRACE_O_TRACEEXIT event, but the WIFEXITED event will be delayed
+until the entire process exits.  This state exists so that shells
+don't think the process is done until all of the threads have exited.
+Unfortunately, signals cannot be delivered to non-waitable zombies.
+Most notably, SIGSTOP cannot be delivered; as a result, when you
+broadcast SIGSTOP to all of the threads, you must not wait for
+non-waitable zombies to stop.  Furthermore, any ptrace command on a
+non-waitable zombie, including PTRACE_DETACH, will return ESRCH.
+
+== Multi-threaded debuggers ==
+
+If the debugger itself is multi-threaded, ptrace calls must come from
+the same thread that originally attached to the remote thread.  The
+kernel simply compares the PID of the caller of ptrace against the
+tracer PID of the process passed to ptrace.  Because each debugger
+thread has a different PID, calling ptrace from a different thread
+might as well be calling it from a different process and the kernel
+will return ESRCH.
+
+wait, on the other hand, does not have this restriction.  Any debugger
+thread can wait on any thread in the attached process.
diff --git a/libgo/go/debug/proc/regs_darwin_386.go b/libgo/go/debug/proc/regs_darwin_386.go
new file mode 100644
index 000000000..60c9ac719
--- /dev/null
+++ b/libgo/go/debug/proc/regs_darwin_386.go
@@ -0,0 +1,5 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
diff --git a/libgo/go/debug/proc/regs_darwin_amd64.go b/libgo/go/debug/proc/regs_darwin_amd64.go
new file mode 100644
index 000000000..60c9ac719
--- /dev/null
+++ b/libgo/go/debug/proc/regs_darwin_amd64.go
@@ -0,0 +1,5 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
diff --git a/libgo/go/debug/proc/regs_freebsd_386.go b/libgo/go/debug/proc/regs_freebsd_386.go
new file mode 100644
index 000000000..60c9ac719
--- /dev/null
+++ b/libgo/go/debug/proc/regs_freebsd_386.go
@@ -0,0 +1,5 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
diff --git a/libgo/go/debug/proc/regs_freebsd_amd64.go b/libgo/go/debug/proc/regs_freebsd_amd64.go
new file mode 100644
index 000000000..60c9ac719
--- /dev/null
+++ b/libgo/go/debug/proc/regs_freebsd_amd64.go
@@ -0,0 +1,5 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
diff --git a/libgo/go/debug/proc/regs_linux_386.go b/libgo/go/debug/proc/regs_linux_386.go
new file mode 100644
index 000000000..b4a9769db
--- /dev/null
+++ b/libgo/go/debug/proc/regs_linux_386.go
@@ -0,0 +1,143 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
+
+import (
+	"os"
+	"strconv"
+	"syscall"
+)
+
+type _386Regs struct {
+	syscall.PtraceRegs
+	setter func(*syscall.PtraceRegs) os.Error
+}
+
+var names = []string{
+	"eax",
+	"ebx",
+	"ecx",
+	"edx",
+	"esi",
+	"edi",
+	"ebp",
+	"esp",
+	"eip",
+	"eflags",
+	"cs",
+	"ss",
+	"ds",
+	"es",
+	"fs",
+	"gs",
+}
+
+func (r *_386Regs) PC() Word { return Word(r.Eip) }
+
+func (r *_386Regs) SetPC(val Word) os.Error {
+	r.Eip = int32(val)
+	return r.setter(&r.PtraceRegs)
+}
+
+func (r *_386Regs) Link() Word {
+	// TODO(austin)
+	panic("No link register")
+}
+
+func (r *_386Regs) SetLink(val Word) os.Error { panic("No link register") }
+
+func (r *_386Regs) SP() Word { return Word(r.Esp) }
+
+func (r *_386Regs) SetSP(val Word) os.Error {
+	r.Esp = int32(val)
+	return r.setter(&r.PtraceRegs)
+}
+
+func (r *_386Regs) Names() []string { return names }
+
+func (r *_386Regs) Get(i int) Word {
+	switch i {
+	case 0:
+		return Word(uint32(r.Eax))
+	case 1:
+		return Word(uint32(r.Ebx))
+	case 2:
+		return Word(uint32(r.Ecx))
+	case 3:
+		return Word(uint32(r.Edx))
+	case 4:
+		return Word(uint32(r.Esi))
+	case 5:
+		return Word(uint32(r.Edi))
+	case 6:
+		return Word(uint32(r.Ebp))
+	case 7:
+		return Word(uint32(r.Esp))
+	case 8:
+		return Word(uint32(r.Eip))
+	case 9:
+		return Word(uint32(r.Eflags))
+	case 10:
+		return Word(r.Xcs)
+	case 11:
+		return Word(r.Xss)
+	case 12:
+		return Word(r.Xds)
+	case 13:
+		return Word(r.Xes)
+	case 14:
+		return Word(r.Xfs)
+	case 15:
+		return Word(r.Xgs)
+	}
+	panic("invalid register index " + strconv.Itoa(i))
+}
+
+func (r *_386Regs) Set(i int, val Word) os.Error {
+	switch i {
+	case 0:
+		r.Eax = int32(val)
+	case 1:
+		r.Ebx = int32(val)
+	case 2:
+		r.Ecx = int32(val)
+	case 3:
+		r.Edx = int32(val)
+	case 4:
+		r.Esi = int32(val)
+	case 5:
+		r.Edi = int32(val)
+	case 6:
+		r.Ebp = int32(val)
+	case 7:
+		r.Esp = int32(val)
+	case 8:
+		r.Eip = int32(val)
+	case 9:
+		r.Eflags = int32(val)
+	case 10:
+		r.Xcs = int32(val)
+	case 11:
+		r.Xss = int32(val)
+	case 12:
+		r.Xds = int32(val)
+	case 13:
+		r.Xes = int32(val)
+	case 14:
+		r.Xfs = int32(val)
+	case 15:
+		r.Xgs = int32(val)
+	default:
+		panic("invalid register index " + strconv.Itoa(i))
+	}
+	return r.setter(&r.PtraceRegs)
+}
+
+func newRegs(regs *syscall.PtraceRegs, setter func(*syscall.PtraceRegs) os.Error) Regs {
+	res := _386Regs{}
+	res.PtraceRegs = *regs
+	res.setter = setter
+	return &res
+}
diff --git a/libgo/go/debug/proc/regs_linux_amd64.go b/libgo/go/debug/proc/regs_linux_amd64.go
new file mode 100644
index 000000000..381be29b1
--- /dev/null
+++ b/libgo/go/debug/proc/regs_linux_amd64.go
@@ -0,0 +1,191 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
+
+import (
+	"os"
+	"strconv"
+	"syscall"
+)
+
+type amd64Regs struct {
+	syscall.PtraceRegs
+	setter func(*syscall.PtraceRegs) os.Error
+}
+
+var names = [...]string{
+	"rax",
+	"rbx",
+	"rcx",
+	"rdx",
+	"rsi",
+	"rdi",
+	"rbp",
+	"rsp",
+	"r8",
+	"r9",
+	"r10",
+	"r11",
+	"r12",
+	"r13",
+	"r14",
+	"r15",
+	"rip",
+	"eflags",
+	"cs",
+	"ss",
+	"ds",
+	"es",
+	"fs",
+	"gs",
+
+	// PtraceRegs contains these registers, but I don't think
+	// they're actually meaningful.
+	//"orig_rax",
+	//"fs_base",
+	//"gs_base",
+}
+
+func (r *amd64Regs) PC() Word { return Word(r.Rip) }
+
+func (r *amd64Regs) SetPC(val Word) os.Error {
+	r.Rip = uint64(val)
+	return r.setter(&r.PtraceRegs)
+}
+
+func (r *amd64Regs) Link() Word {
+	// TODO(austin)
+	panic("No link register")
+}
+
+func (r *amd64Regs) SetLink(val Word) os.Error {
+	panic("No link register")
+}
+
+func (r *amd64Regs) SP() Word { return Word(r.Rsp) }
+
+func (r *amd64Regs) SetSP(val Word) os.Error {
+	r.Rsp = uint64(val)
+	return r.setter(&r.PtraceRegs)
+}
+
+func (r *amd64Regs) Names() []string { return names[0:] }
+
+func (r *amd64Regs) Get(i int) Word {
+	switch i {
+	case 0:
+		return Word(r.Rax)
+	case 1:
+		return Word(r.Rbx)
+	case 2:
+		return Word(r.Rcx)
+	case 3:
+		return Word(r.Rdx)
+	case 4:
+		return Word(r.Rsi)
+	case 5:
+		return Word(r.Rdi)
+	case 6:
+		return Word(r.Rbp)
+	case 7:
+		return Word(r.Rsp)
+	case 8:
+		return Word(r.R8)
+	case 9:
+		return Word(r.R9)
+	case 10:
+		return Word(r.R10)
+	case 11:
+		return Word(r.R11)
+	case 12:
+		return Word(r.R12)
+	case 13:
+		return Word(r.R13)
+	case 14:
+		return Word(r.R14)
+	case 15:
+		return Word(r.R15)
+	case 16:
+		return Word(r.Rip)
+	case 17:
+		return Word(r.Eflags)
+	case 18:
+		return Word(r.Cs)
+	case 19:
+		return Word(r.Ss)
+	case 20:
+		return Word(r.Ds)
+	case 21:
+		return Word(r.Es)
+	case 22:
+		return Word(r.Fs)
+	case 23:
+		return Word(r.Gs)
+	}
+	panic("invalid register index " + strconv.Itoa(i))
+}
+
+func (r *amd64Regs) Set(i int, val Word) os.Error {
+	switch i {
+	case 0:
+		r.Rax = uint64(val)
+	case 1:
+		r.Rbx = uint64(val)
+	case 2:
+		r.Rcx = uint64(val)
+	case 3:
+		r.Rdx = uint64(val)
+	case 4:
+		r.Rsi = uint64(val)
+	case 5:
+		r.Rdi = uint64(val)
+	case 6:
+		r.Rbp = uint64(val)
+	case 7:
+		r.Rsp = uint64(val)
+	case 8:
+		r.R8 = uint64(val)
+	case 9:
+		r.R9 = uint64(val)
+	case 10:
+		r.R10 = uint64(val)
+	case 11:
+		r.R11 = uint64(val)
+	case 12:
+		r.R12 = uint64(val)
+	case 13:
+		r.R13 = uint64(val)
+	case 14:
+		r.R14 = uint64(val)
+	case 15:
+		r.R15 = uint64(val)
+	case 16:
+		r.Rip = uint64(val)
+	case 17:
+		r.Eflags = uint64(val)
+	case 18:
+		r.Cs = uint64(val)
+	case 19:
+		r.Ss = uint64(val)
+	case 20:
+		r.Ds = uint64(val)
+	case 21:
+		r.Es = uint64(val)
+	case 22:
+		r.Fs = uint64(val)
+	case 23:
+		r.Gs = uint64(val)
+	default:
+		panic("invalid register index " + strconv.Itoa(i))
+	}
+	return r.setter(&r.PtraceRegs)
+}
+
+func newRegs(regs *syscall.PtraceRegs, setter func(*syscall.PtraceRegs) os.Error) Regs {
+	res := amd64Regs{}
+	res.PtraceRegs = *regs
+	res.setter = setter
+	return &res
+}
diff --git a/libgo/go/debug/proc/regs_linux_arm.go b/libgo/go/debug/proc/regs_linux_arm.go
new file mode 100644
index 000000000..ec78cbcf2
--- /dev/null
+++ b/libgo/go/debug/proc/regs_linux_arm.go
@@ -0,0 +1,39 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
+
+import (
+	"os"
+	"syscall"
+)
+
+// TODO(kaib): add support
+
+type armRegs struct{}
+
+func (r *armRegs) PC() Word { return Word(0) }
+
+func (r *armRegs) SetPC(val Word) os.Error { return nil }
+
+func (r *armRegs) Link() Word { return Word(0) }
+
+func (r *armRegs) SetLink(val Word) os.Error { return nil }
+
+func (r *armRegs) SP() Word { return Word(0) }
+
+func (r *armRegs) SetSP(val Word) os.Error { return nil }
+
+func (r *armRegs) Names() []string { return nil }
+
+func (r *armRegs) Get(i int) Word { return Word(0) }
+
+func (r *armRegs) Set(i int, val Word) os.Error {
+	return nil
+}
+
+func newRegs(regs *syscall.PtraceRegs, setter func(*syscall.PtraceRegs) os.Error) Regs {
+	res := armRegs{}
+	return &res
+}
diff --git a/libgo/go/debug/proc/regs_windows_386.go b/libgo/go/debug/proc/regs_windows_386.go
new file mode 100644
index 000000000..60c9ac719
--- /dev/null
+++ b/libgo/go/debug/proc/regs_windows_386.go
@@ -0,0 +1,5 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
diff --git a/libgo/go/debug/proc/regs_windows_amd64.go b/libgo/go/debug/proc/regs_windows_amd64.go
new file mode 100644
index 000000000..60c9ac719
--- /dev/null
+++ b/libgo/go/debug/proc/regs_windows_amd64.go
@@ -0,0 +1,5 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proc
author	upstream source tree <ports@midipix.org>	2015-03-15 20:14:05 -0400
committer	upstream source tree <ports@midipix.org>	2015-03-15 20:14:05 -0400
commit	554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree	976dc5ab7fddf506dadce60ae936f43f58787092 /libgo/go/debug
download	cbb-gcc-4.6.4-554fd8c5195424bdbcabf5de30fdc183aba391bd.tar.bz2 cbb-gcc-4.6.4-554fd8c5195424bdbcabf5de30fdc183aba391bd.tar.xz