libgo: Update to go1.6rc1.

    
    Reviewed-on: https://go-review.googlesource.com/19200

From-SVN: r233110

20 files changed, 969 insertions, 133 deletions

diff --git a/libgo/go/debug/dwarf/class_string.go b/libgo/go/debug/dwarf/class_string.go
index 0b1206b..d57d9f7 100644
--- a/libgo/go/debug/dwarf/class_string.go
+++ b/libgo/go/debug/dwarf/class_string.go
@@ -4,14 +4,13 @@ package dwarf
 
 import "fmt"
 
-const _Class_name = "ClassAddressClassBlockClassConstantClassExprLocClassFlagClassLinePtrClassLocListPtrClassMacPtrClassRangeListPtrClassReferenceClassReferenceSigClassStringClassReferenceAltClassStringAlt"
+const _Class_name = "ClassUnknownClassAddressClassBlockClassConstantClassExprLocClassFlagClassLinePtrClassLocListPtrClassMacPtrClassRangeListPtrClassReferenceClassReferenceSigClassStringClassReferenceAltClassStringAlt"
 
-var _Class_index = [...]uint8{0, 12, 22, 35, 47, 56, 68, 83, 94, 111, 125, 142, 153, 170, 184}
+var _Class_index = [...]uint8{0, 12, 24, 34, 47, 59, 68, 80, 95, 106, 123, 137, 154, 165, 182, 196}
 
 func (i Class) String() string {
-	i -= 1
 	if i < 0 || i+1 >= Class(len(_Class_index)) {
-		return fmt.Sprintf("Class(%d)", i+1)
+		return fmt.Sprintf("Class(%d)", i)
 	}
 	return _Class_name[_Class_index[i]:_Class_index[i+1]]
 }
diff --git a/libgo/go/debug/dwarf/entry.go b/libgo/go/debug/dwarf/entry.go
index d607e5b..5ca8667 100644
--- a/libgo/go/debug/dwarf/entry.go
+++ b/libgo/go/debug/dwarf/entry.go
@@ -193,8 +193,7 @@ func formToClass(form format, attr Attr, vers int, b *buf) Class {
 		if class, ok := attrPtrClass[attr]; ok {
 			return class
 		}
-		b.error("cannot determine class of unknown attribute with formSecOffset")
-		return 0
+		return ClassUnknown
 
 	case formExprloc:
 		return ClassExprLoc
@@ -235,6 +234,9 @@ type Entry struct {
 //    loclistptr        int64          ClassLocListPtr
 //    macptr            int64          ClassMacPtr
 //    rangelistptr      int64          ClassRangeListPtr
+//
+// For unrecognized or vendor-defined attributes, Class may be
+// ClassUnknown.
 type Field struct {
 	Attr  Attr
 	Val   interface{}
@@ -258,9 +260,12 @@ type Field struct {
 type Class int
 
 const (
+	// ClassUnknown represents values of unknown DWARF class.
+	ClassUnknown Class = iota
+
 	// ClassAddress represents values of type uint64 that are
 	// addresses on the target machine.
-	ClassAddress Class = 1 + iota
+	ClassAddress
 
 	// ClassBlock represents values of type []byte whose
 	// interpretation depends on the attribute.
diff --git a/libgo/go/debug/dwarf/entry_test.go b/libgo/go/debug/dwarf/entry_test.go
new file mode 100644
index 0000000..8bd2d2a
--- /dev/null
+++ b/libgo/go/debug/dwarf/entry_test.go
@@ -0,0 +1,36 @@
+// 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"
+	"testing"
+)
+
+func TestSplit(t *testing.T) {
+	// debug/dwarf doesn't (currently) support split DWARF, but
+	// the attributes that pointed to the split DWARF used to
+	// cause loading the DWARF data to fail entirely (issue
+	// #12592). Test that we can at least read the DWARF data.
+	d := elfData(t, "testdata/split.elf")
+	r := d.Reader()
+	e, err := r.Next()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if e.Tag != TagCompileUnit {
+		t.Fatalf("bad tag: have %s, want %s", e.Tag, TagCompileUnit)
+	}
+	// Check that we were able to parse the unknown section offset
+	// field, even if we can't figure out its DWARF class.
+	const AttrGNUAddrBase Attr = 0x2133
+	f := e.AttrField(AttrGNUAddrBase)
+	if _, ok := f.Val.(int64); !ok {
+		t.Fatalf("bad attribute value type: have %T, want int64", f.Val)
+	}
+	if f.Class != ClassUnknown {
+		t.Fatalf("bad class: have %s, want %s", f.Class, ClassUnknown)
+	}
+}
diff --git a/libgo/go/debug/dwarf/testdata/cycle.c b/libgo/go/debug/dwarf/testdata/cycle.c
new file mode 100644
index 0000000..a0b53df
--- /dev/null
+++ b/libgo/go/debug/dwarf/testdata/cycle.c
@@ -0,0 +1,7 @@
+typedef struct aaa *AAA;
+typedef AAA BBB;
+struct aaa { BBB val; };
+
+AAA x(void) {
+    return (AAA)0;
+}
diff --git a/libgo/go/debug/dwarf/testdata/cycle.elf b/libgo/go/debug/dwarf/testdata/cycle.elf
new file mode 100644
index 0000000..e0b66ca
--- /dev/null
+++ b/libgo/go/debug/dwarf/testdata/cycle.elf
diff --git a/libgo/go/debug/dwarf/testdata/split.c b/libgo/go/debug/dwarf/testdata/split.c
new file mode 100644
index 0000000..0ef3427
--- /dev/null
+++ b/libgo/go/debug/dwarf/testdata/split.c
@@ -0,0 +1,5 @@
+// gcc -gsplit-dwarf split.c -o split.elf
+
+int main() 
+{
+}
diff --git a/libgo/go/debug/dwarf/testdata/split.elf b/libgo/go/debug/dwarf/testdata/split.elf
new file mode 100644
index 0000000..99ee2c2
--- /dev/null
+++ b/libgo/go/debug/dwarf/testdata/split.elf
diff --git a/libgo/go/debug/dwarf/type.go b/libgo/go/debug/dwarf/type.go
index a5daa1d..c76a472 100644
--- a/libgo/go/debug/dwarf/type.go
+++ b/libgo/go/debug/dwarf/type.go
@@ -275,12 +275,14 @@ type typeReader interface {
 
 // Type reads the type at off in the DWARF ``info'' section.
 func (d *Data) Type(off Offset) (Type, error) {
-	return d.readType("info", d.Reader(), off, d.typeCache)
+	return d.readType("info", d.Reader(), off, d.typeCache, nil)
 }
 
-// readType reads a type from r at off of name using and updating a
-// type cache.
-func (d *Data) readType(name string, r typeReader, off Offset, typeCache map[Offset]Type) (Type, error) {
+// readType reads a type from r at off of name. It adds types to the
+// type cache, appends new typedef types to typedefs, and computes the
+// sizes of types. Callers should pass nil for typedefs; this is used
+// for internal recursion.
+func (d *Data) readType(name string, r typeReader, off Offset, typeCache map[Offset]Type, typedefs *[]*TypedefType) (Type, error) {
 	if t, ok := typeCache[off]; ok {
 		return t, nil
 	}
@@ -294,9 +296,24 @@ func (d *Data) readType(name string, r typeReader, off Offset, typeCache map[Off
 		return nil, DecodeError{name, off, "no type at offset"}
 	}
 
+	// If this is the root of the recursion, prepare to resolve
+	// typedef sizes once the recursion is done. This must be done
+	// after the type graph is constructed because it may need to
+	// resolve cycles in a different order than readType
+	// encounters them.
+	if typedefs == nil {
+		var typedefList []*TypedefType
+		defer func() {
+			for _, t := range typedefList {
+				t.Common().ByteSize = t.Type.Size()
+			}
+		}()
+		typedefs = &typedefList
+	}
+
 	// Parse type from Entry.
 	// Must always set typeCache[off] before calling
-	// d.Type recursively, to handle circular types correctly.
+	// d.readType recursively, to handle circular types correctly.
 	var typ Type
 
 	nextDepth := 0
@@ -345,7 +362,7 @@ func (d *Data) readType(name string, r typeReader, off Offset, typeCache map[Off
 		var t Type
 		switch toff := tval.(type) {
 		case Offset:
-			if t, err = d.readType(name, r.clone(), toff, typeCache); err != nil {
+			if t, err = d.readType(name, r.clone(), toff, typeCache, typedefs); err != nil {
 				return nil
 			}
 		case uint64:
@@ -674,7 +691,10 @@ func (d *Data) readType(name string, r typeReader, off Offset, typeCache map[Off
 			b = -1
 			switch t := typ.(type) {
 			case *TypedefType:
-				b = t.Type.Size()
+				// Record that we need to resolve this
+				// type's size once the type graph is
+				// constructed.
+				*typedefs = append(*typedefs, t)
 			case *PtrType:
 				b = int64(addressSize)
 			}
diff --git a/libgo/go/debug/dwarf/type_test.go b/libgo/go/debug/dwarf/type_test.go
index 2cb85e7..ad6308d 100644
--- a/libgo/go/debug/dwarf/type_test.go
+++ b/libgo/go/debug/dwarf/type_test.go
@@ -120,3 +120,37 @@ func testTypedefs(t *testing.T, d *Data, kind string) {
 		}
 	}
 }
+
+func TestTypedefCycle(t *testing.T) {
+	// See issue #13039: reading a typedef cycle starting from a
+	// different place than the size needed to be computed from
+	// used to crash.
+	//
+	// cycle.elf built with GCC 4.8.4:
+	//    gcc -g -c -o cycle.elf cycle.c
+	d := elfData(t, "testdata/cycle.elf")
+	r := d.Reader()
+	offsets := []Offset{}
+	for {
+		e, err := r.Next()
+		if err != nil {
+			t.Fatal("r.Next:", err)
+		}
+		if e == nil {
+			break
+		}
+		switch e.Tag {
+		case TagBaseType, TagTypedef, TagPointerType, TagStructType:
+			offsets = append(offsets, e.Offset)
+		}
+	}
+
+	// Parse each type with a fresh type cache.
+	for _, offset := range offsets {
+		d := elfData(t, "testdata/cycle.elf")
+		_, err := d.Type(offset)
+		if err != nil {
+			t.Fatalf("d.Type(0x%x): %s", offset, err)
+		}
+	}
+}
diff --git a/libgo/go/debug/dwarf/typeunit.go b/libgo/go/debug/dwarf/typeunit.go
index 9cfb4a8..0f4e07e 100644
--- a/libgo/go/debug/dwarf/typeunit.go
+++ b/libgo/go/debug/dwarf/typeunit.go
@@ -101,7 +101,7 @@ func (d *Data) sigToType(sig uint64) (Type, error) {
 
 	b := makeBuf(d, tu, tu.name, tu.off, tu.data)
 	r := &typeUnitReader{d: d, tu: tu, b: b}
-	t, err := d.readType(tu.name, r, Offset(tu.toff), make(map[Offset]Type))
+	t, err := d.readType(tu.name, r, Offset(tu.toff), make(map[Offset]Type), nil)
 	if err != nil {
 		return nil, err
 	}
diff --git a/libgo/go/debug/elf/elf.go b/libgo/go/debug/elf/elf.go
index c97ccaa..6086b54 100644
--- a/libgo/go/debug/elf/elf.go
+++ b/libgo/go/debug/elf/elf.go
@@ -411,6 +411,7 @@ const (
 	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_COMPRESSED       SectionFlag = 0x800      /* Section is compressed. */
 	SHF_MASKOS           SectionFlag = 0x0ff00000 /* OS-specific semantics. */
 	SHF_MASKPROC         SectionFlag = 0xf0000000 /* Processor-specific semantics. */
 )
@@ -426,11 +427,34 @@ var shfStrings = []intName{
 	{0x100, "SHF_OS_NONCONFORMING"},
 	{0x200, "SHF_GROUP"},
 	{0x400, "SHF_TLS"},
+	{0x800, "SHF_COMPRESSED"},
 }
 
 func (i SectionFlag) String() string   { return flagName(uint32(i), shfStrings, false) }
 func (i SectionFlag) GoString() string { return flagName(uint32(i), shfStrings, true) }
 
+// Section compression type.
+type CompressionType int
+
+const (
+	COMPRESS_ZLIB   CompressionType = 1          /* ZLIB compression. */
+	COMPRESS_LOOS   CompressionType = 0x60000000 /* First OS-specific. */
+	COMPRESS_HIOS   CompressionType = 0x6fffffff /* Last OS-specific. */
+	COMPRESS_LOPROC CompressionType = 0x70000000 /* First processor-specific type. */
+	COMPRESS_HIPROC CompressionType = 0x7fffffff /* Last processor-specific type. */
+)
+
+var compressionStrings = []intName{
+	{0, "COMPRESS_ZLIB"},
+	{0x60000000, "COMPRESS_LOOS"},
+	{0x6fffffff, "COMPRESS_HIOS"},
+	{0x70000000, "COMPRESS_LOPROC"},
+	{0x7fffffff, "COMPRESS_HIPROC"},
+}
+
+func (i CompressionType) String() string   { return stringName(uint32(i), compressionStrings, false) }
+func (i CompressionType) GoString() string { return stringName(uint32(i), compressionStrings, true) }
+
 // Prog.Type
 type ProgType int
 
@@ -1246,6 +1270,115 @@ var r386Strings = []intName{
 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 MIPS.
+type R_MIPS int
+
+const (
+	R_MIPS_NONE          R_MIPS = 0
+	R_MIPS_16            R_MIPS = 1
+	R_MIPS_32            R_MIPS = 2
+	R_MIPS_REL32         R_MIPS = 3
+	R_MIPS_26            R_MIPS = 4
+	R_MIPS_HI16          R_MIPS = 5  /* high 16 bits of symbol value */
+	R_MIPS_LO16          R_MIPS = 6  /* low 16 bits of symbol value */
+	R_MIPS_GPREL16       R_MIPS = 7  /* GP-relative reference  */
+	R_MIPS_LITERAL       R_MIPS = 8  /* Reference to literal section  */
+	R_MIPS_GOT16         R_MIPS = 9  /* Reference to global offset table */
+	R_MIPS_PC16          R_MIPS = 10 /* 16 bit PC relative reference */
+	R_MIPS_CALL16        R_MIPS = 11 /* 16 bit call thru glbl offset tbl */
+	R_MIPS_GPREL32       R_MIPS = 12
+	R_MIPS_SHIFT5        R_MIPS = 16
+	R_MIPS_SHIFT6        R_MIPS = 17
+	R_MIPS_64            R_MIPS = 18
+	R_MIPS_GOT_DISP      R_MIPS = 19
+	R_MIPS_GOT_PAGE      R_MIPS = 20
+	R_MIPS_GOT_OFST      R_MIPS = 21
+	R_MIPS_GOT_HI16      R_MIPS = 22
+	R_MIPS_GOT_LO16      R_MIPS = 23
+	R_MIPS_SUB           R_MIPS = 24
+	R_MIPS_INSERT_A      R_MIPS = 25
+	R_MIPS_INSERT_B      R_MIPS = 26
+	R_MIPS_DELETE        R_MIPS = 27
+	R_MIPS_HIGHER        R_MIPS = 28
+	R_MIPS_HIGHEST       R_MIPS = 29
+	R_MIPS_CALL_HI16     R_MIPS = 30
+	R_MIPS_CALL_LO16     R_MIPS = 31
+	R_MIPS_SCN_DISP      R_MIPS = 32
+	R_MIPS_REL16         R_MIPS = 33
+	R_MIPS_ADD_IMMEDIATE R_MIPS = 34
+	R_MIPS_PJUMP         R_MIPS = 35
+	R_MIPS_RELGOT        R_MIPS = 36
+	R_MIPS_JALR          R_MIPS = 37
+
+	R_MIPS_TLS_DTPMOD32    R_MIPS = 38 /* Module number 32 bit */
+	R_MIPS_TLS_DTPREL32    R_MIPS = 39 /* Module-relative offset 32 bit */
+	R_MIPS_TLS_DTPMOD64    R_MIPS = 40 /* Module number 64 bit */
+	R_MIPS_TLS_DTPREL64    R_MIPS = 41 /* Module-relative offset 64 bit */
+	R_MIPS_TLS_GD          R_MIPS = 42 /* 16 bit GOT offset for GD */
+	R_MIPS_TLS_LDM         R_MIPS = 43 /* 16 bit GOT offset for LDM */
+	R_MIPS_TLS_DTPREL_HI16 R_MIPS = 44 /* Module-relative offset, high 16 bits */
+	R_MIPS_TLS_DTPREL_LO16 R_MIPS = 45 /* Module-relative offset, low 16 bits */
+	R_MIPS_TLS_GOTTPREL    R_MIPS = 46 /* 16 bit GOT offset for IE */
+	R_MIPS_TLS_TPREL32     R_MIPS = 47 /* TP-relative offset, 32 bit */
+	R_MIPS_TLS_TPREL64     R_MIPS = 48 /* TP-relative offset, 64 bit */
+	R_MIPS_TLS_TPREL_HI16  R_MIPS = 49 /* TP-relative offset, high 16 bits */
+	R_MIPS_TLS_TPREL_LO16  R_MIPS = 50 /* TP-relative offset, low 16 bits */
+)
+
+var rmipsStrings = []intName{
+	{0, "R_MIPS_NONE"},
+	{1, "R_MIPS_16"},
+	{2, "R_MIPS_32"},
+	{3, "R_MIPS_REL32"},
+	{4, "R_MIPS_26"},
+	{5, "R_MIPS_HI16"},
+	{6, "R_MIPS_LO16"},
+	{7, "R_MIPS_GPREL16"},
+	{8, "R_MIPS_LITERAL"},
+	{9, "R_MIPS_GOT16"},
+	{10, "R_MIPS_PC16"},
+	{11, "R_MIPS_CALL16"},
+	{12, "R_MIPS_GPREL32"},
+	{16, "R_MIPS_SHIFT5"},
+	{17, "R_MIPS_SHIFT6"},
+	{18, "R_MIPS_64"},
+	{19, "R_MIPS_GOT_DISP"},
+	{20, "R_MIPS_GOT_PAGE"},
+	{21, "R_MIPS_GOT_OFST"},
+	{22, "R_MIPS_GOT_HI16"},
+	{23, "R_MIPS_GOT_LO16"},
+	{24, "R_MIPS_SUB"},
+	{25, "R_MIPS_INSERT_A"},
+	{26, "R_MIPS_INSERT_B"},
+	{27, "R_MIPS_DELETE"},
+	{28, "R_MIPS_HIGHER"},
+	{29, "R_MIPS_HIGHEST"},
+	{30, "R_MIPS_CALL_HI16"},
+	{31, "R_MIPS_CALL_LO16"},
+	{32, "R_MIPS_SCN_DISP"},
+	{33, "R_MIPS_REL16"},
+	{34, "R_MIPS_ADD_IMMEDIATE"},
+	{35, "R_MIPS_PJUMP"},
+	{36, "R_MIPS_RELGOT"},
+	{37, "R_MIPS_JALR"},
+	{38, "R_MIPS_TLS_DTPMOD32"},
+	{39, "R_MIPS_TLS_DTPREL32"},
+	{40, "R_MIPS_TLS_DTPMOD64"},
+	{41, "R_MIPS_TLS_DTPREL64"},
+	{42, "R_MIPS_TLS_GD"},
+	{43, "R_MIPS_TLS_LDM"},
+	{44, "R_MIPS_TLS_DTPREL_HI16"},
+	{45, "R_MIPS_TLS_DTPREL_LO16"},
+	{46, "R_MIPS_TLS_GOTTPREL"},
+	{47, "R_MIPS_TLS_TPREL32"},
+	{48, "R_MIPS_TLS_TPREL64"},
+	{49, "R_MIPS_TLS_TPREL_HI16"},
+	{50, "R_MIPS_TLS_TPREL_LO16"},
+}
+
+func (i R_MIPS) String() string   { return stringName(uint32(i), rmipsStrings, false) }
+func (i R_MIPS) GoString() string { return stringName(uint32(i), rmipsStrings, true) }
+
 // Relocation types for PowerPC.
 type R_PPC int
 
@@ -1835,6 +1968,13 @@ type Dyn32 struct {
 	Val uint32 /* Integer/Address value. */
 }
 
+// ELF32 Compression header.
+type Chdr32 struct {
+	Type      uint32
+	Size      uint32
+	Addralign uint32
+}
+
 /*
  * Relocation entries.
  */
@@ -1929,6 +2069,14 @@ type Dyn64 struct {
 	Val uint64 /* Integer/address value */
 }
 
+// ELF64 Compression header.
+type Chdr64 struct {
+	Type      uint32
+	_         uint32 /* Reserved. */
+	Size      uint64
+	Addralign uint64
+}
+
 /*
  * Relocation entries.
  */
diff --git a/libgo/go/debug/elf/file.go b/libgo/go/debug/elf/file.go
index 370c5e6..b028772 100644
--- a/libgo/go/debug/elf/file.go
+++ b/libgo/go/debug/elf/file.go
@@ -7,6 +7,7 @@ package elf
 
 import (
 	"bytes"
+	"compress/zlib"
 	"debug/dwarf"
 	"encoding/binary"
 	"errors"
@@ -57,6 +58,12 @@ type SectionHeader struct {
 	Info      uint32
 	Addralign uint64
 	Entsize   uint64
+
+	// FileSize is the size of this section in the file in bytes.
+	// If a section is compressed, FileSize is the size of the
+	// compressed data, while Size (above) is the size of the
+	// uncompressed data.
+	FileSize uint64
 }
 
 // A Section represents a single section in an ELF file.
@@ -69,17 +76,23 @@ type Section struct {
 	// If a client wants Read and Seek it must use
 	// Open() to avoid fighting over the seek offset
 	// with other clients.
+	//
+	// ReaderAt may be nil if the section is not easily available
+	// in a random-access form. For example, a compressed section
+	// may have a nil ReaderAt.
 	io.ReaderAt
 	sr *io.SectionReader
+
+	compressionType   CompressionType
+	compressionOffset int64
 }
 
 // Data reads and returns the contents of the ELF section.
+// Even if the section is stored compressed in the ELF file,
+// Data returns uncompressed data.
 func (s *Section) Data() ([]byte, error) {
-	dat := make([]byte, s.sr.Size())
-	n, err := s.sr.ReadAt(dat, 0)
-	if n == len(dat) {
-		err = nil
-	}
+	dat := make([]byte, s.Size)
+	n, err := io.ReadFull(s.Open(), dat)
 	return dat[0:n], err
 }
 
@@ -93,7 +106,24 @@ func (f *File) stringTable(link uint32) ([]byte, error) {
 }
 
 // Open returns a new ReadSeeker reading the ELF section.
-func (s *Section) Open() io.ReadSeeker { return io.NewSectionReader(s.sr, 0, 1<<63-1) }
+// Even if the section is stored compressed in the ELF file,
+// the ReadSeeker reads uncompressed data.
+func (s *Section) Open() io.ReadSeeker {
+	if s.Flags&SHF_COMPRESSED == 0 {
+		return io.NewSectionReader(s.sr, 0, 1<<63-1)
+	}
+	if s.compressionType == COMPRESS_ZLIB {
+		return &readSeekerFromReader{
+			reset: func() (io.Reader, error) {
+				fr := io.NewSectionReader(s.sr, s.compressionOffset, int64(s.FileSize)-s.compressionOffset)
+				return zlib.NewReader(fr)
+			},
+			size: int64(s.Size),
+		}
+	}
+	err := &FormatError{int64(s.Offset), "unknown compression type", s.compressionType}
+	return errorReader{err}
+}
 
 // A ProgHeader represents a single ELF program header.
 type ProgHeader struct {
@@ -343,7 +373,7 @@ func NewFile(r io.ReaderAt) (*File, error) {
 				Flags:     SectionFlag(sh.Flags),
 				Addr:      uint64(sh.Addr),
 				Offset:    uint64(sh.Off),
-				Size:      uint64(sh.Size),
+				FileSize:  uint64(sh.Size),
 				Link:      uint32(sh.Link),
 				Info:      uint32(sh.Info),
 				Addralign: uint64(sh.Addralign),
@@ -359,7 +389,7 @@ func NewFile(r io.ReaderAt) (*File, error) {
 				Type:      SectionType(sh.Type),
 				Flags:     SectionFlag(sh.Flags),
 				Offset:    uint64(sh.Off),
-				Size:      uint64(sh.Size),
+				FileSize:  uint64(sh.Size),
 				Addr:      uint64(sh.Addr),
 				Link:      uint32(sh.Link),
 				Info:      uint32(sh.Info),
@@ -367,8 +397,35 @@ func NewFile(r io.ReaderAt) (*File, error) {
 				Entsize:   uint64(sh.Entsize),
 			}
 		}
-		s.sr = io.NewSectionReader(r, int64(s.Offset), int64(s.Size))
-		s.ReaderAt = s.sr
+		s.sr = io.NewSectionReader(r, int64(s.Offset), int64(s.FileSize))
+
+		if s.Flags&SHF_COMPRESSED == 0 {
+			s.ReaderAt = s.sr
+			s.Size = s.FileSize
+		} else {
+			// Read the compression header.
+			switch f.Class {
+			case ELFCLASS32:
+				ch := new(Chdr32)
+				if err := binary.Read(s.sr, f.ByteOrder, ch); err != nil {
+					return nil, err
+				}
+				s.compressionType = CompressionType(ch.Type)
+				s.Size = uint64(ch.Size)
+				s.Addralign = uint64(ch.Addralign)
+				s.compressionOffset = int64(binary.Size(ch))
+			case ELFCLASS64:
+				ch := new(Chdr64)
+				if err := binary.Read(s.sr, f.ByteOrder, ch); err != nil {
+					return nil, err
+				}
+				s.compressionType = CompressionType(ch.Type)
+				s.Size = ch.Size
+				s.Addralign = ch.Addralign
+				s.compressionOffset = int64(binary.Size(ch))
+			}
+		}
+
 		f.Sections[i] = s
 	}
 
@@ -537,6 +594,8 @@ func (f *File) applyRelocations(dst []byte, rels []byte) error {
 		return f.applyRelocationsPPC(dst, rels)
 	case f.Class == ELFCLASS64 && f.Machine == EM_PPC64:
 		return f.applyRelocationsPPC64(dst, rels)
+	case f.Class == ELFCLASS64 && f.Machine == EM_MIPS:
+		return f.applyRelocationsMIPS64(dst, rels)
 	case f.Class == ELFCLASS64 && f.Machine == EM_S390:
 		return f.applyRelocationsS390x(dst, rels)
 	default:
@@ -802,6 +861,58 @@ func (f *File) applyRelocationsPPC64(dst []byte, rels []byte) error {
 	return nil
 }
 
+func (f *File) applyRelocationsMIPS64(dst []byte, rels []byte) error {
+	// 24 is the size of Rela64.
+	if len(rels)%24 != 0 {
+		return errors.New("length of relocation section is not a multiple of 24")
+	}
+
+	symbols, _, err := f.getSymbols(SHT_SYMTAB)
+	if err != nil {
+		return err
+	}
+
+	b := bytes.NewReader(rels)
+	var rela Rela64
+
+	for b.Len() > 0 {
+		binary.Read(b, f.ByteOrder, &rela)
+		var symNo uint64
+		var t R_MIPS
+		if f.ByteOrder == binary.BigEndian {
+			symNo = rela.Info >> 32
+			t = R_MIPS(rela.Info & 0xff)
+		} else {
+			symNo = rela.Info & 0xffffffff
+			t = R_MIPS(rela.Info >> 56)
+		}
+
+		if symNo == 0 || symNo > uint64(len(symbols)) {
+			continue
+		}
+		sym := &symbols[symNo-1]
+		if SymType(sym.Info&0xf) != STT_SECTION {
+			// We don't handle non-section relocations for now.
+			continue
+		}
+
+		switch t {
+		case R_MIPS_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_MIPS_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) applyRelocationsS390x(dst []byte, rels []byte) error {
 	// 24 is the size of Rela64.
 	if len(rels)%24 != 0 {
@@ -852,6 +963,22 @@ func (f *File) DWARF() (*dwarf.Data, error) {
 			return nil, err
 		}
 
+		if len(b) >= 12 && string(b[:4]) == "ZLIB" {
+			dlen := binary.BigEndian.Uint64(b[4:12])
+			dbuf := make([]byte, dlen)
+			r, err := zlib.NewReader(bytes.NewBuffer(b[12:]))
+			if err != nil {
+				return nil, err
+			}
+			if _, err := io.ReadFull(r, dbuf); err != nil {
+				return nil, err
+			}
+			if err := r.Close(); err != nil {
+				return nil, err
+			}
+			b = dbuf
+		}
+
 		for _, r := range f.Sections {
 			if r.Type != SHT_RELA && r.Type != SHT_REL {
 				continue
@@ -876,17 +1003,23 @@ func (f *File) DWARF() (*dwarf.Data, error) {
 	// Don't bother loading others.
 	var dat = map[string][]byte{"abbrev": nil, "info": nil, "str": nil, "line": nil, "ranges": nil}
 	for i, s := range f.Sections {
-		if !strings.HasPrefix(s.Name, ".debug_") {
+		suffix := ""
+		switch {
+		case strings.HasPrefix(s.Name, ".debug_"):
+			suffix = s.Name[7:]
+		case strings.HasPrefix(s.Name, ".zdebug_"):
+			suffix = s.Name[8:]
+		default:
 			continue
 		}
-		if _, ok := dat[s.Name[7:]]; !ok {
+		if _, ok := dat[suffix]; !ok {
 			continue
 		}
 		b, err := sectionData(i, s)
 		if err != nil {
 			return nil, err
 		}
-		dat[s.Name[7:]] = b
+		dat[suffix] = b
 	}
 
 	d, err := dwarf.New(dat["abbrev"], nil, nil, dat["info"], dat["line"], nil, dat["ranges"], dat["str"])
diff --git a/libgo/go/debug/elf/file_test.go b/libgo/go/debug/elf/file_test.go
index 1ad4314..5c0df0f 100644
--- a/libgo/go/debug/elf/file_test.go
+++ b/libgo/go/debug/elf/file_test.go
@@ -10,6 +10,7 @@ import (
 	"debug/dwarf"
 	"encoding/binary"
 	"io"
+	"math/rand"
 	"net"
 	"os"
 	"path"
@@ -31,36 +32,36 @@ var fileTests = []fileTest{
 		"testdata/gcc-386-freebsd-exec",
 		FileHeader{ELFCLASS32, ELFDATA2LSB, EV_CURRENT, ELFOSABI_FREEBSD, 0, binary.LittleEndian, ET_EXEC, EM_386, 0x80483cc},
 		[]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},
+			{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+			{".interp", SHT_PROGBITS, SHF_ALLOC, 0x80480d4, 0xd4, 0x15, 0x0, 0x0, 0x1, 0x0, 0x15},
+			{".hash", SHT_HASH, SHF_ALLOC, 0x80480ec, 0xec, 0x90, 0x3, 0x0, 0x4, 0x4, 0x90},
+			{".dynsym", SHT_DYNSYM, SHF_ALLOC, 0x804817c, 0x17c, 0x110, 0x4, 0x1, 0x4, 0x10, 0x110},
+			{".dynstr", SHT_STRTAB, SHF_ALLOC, 0x804828c, 0x28c, 0xbb, 0x0, 0x0, 0x1, 0x0, 0xbb},
+			{".rel.plt", SHT_REL, SHF_ALLOC, 0x8048348, 0x348, 0x20, 0x3, 0x7, 0x4, 0x8, 0x20},
+			{".init", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x8048368, 0x368, 0x11, 0x0, 0x0, 0x4, 0x0, 0x11},
+			{".plt", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x804837c, 0x37c, 0x50, 0x0, 0x0, 0x4, 0x4, 0x50},
+			{".text", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x80483cc, 0x3cc, 0x180, 0x0, 0x0, 0x4, 0x0, 0x180},
+			{".fini", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x804854c, 0x54c, 0xc, 0x0, 0x0, 0x4, 0x0, 0xc},
+			{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x8048558, 0x558, 0xa3, 0x0, 0x0, 0x1, 0x0, 0xa3},
+			{".data", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80495fc, 0x5fc, 0xc, 0x0, 0x0, 0x4, 0x0, 0xc},
+			{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x8049608, 0x608, 0x4, 0x0, 0x0, 0x4, 0x0, 0x4},
+			{".dynamic", SHT_DYNAMIC, SHF_WRITE + SHF_ALLOC, 0x804960c, 0x60c, 0x98, 0x4, 0x0, 0x4, 0x8, 0x98},
+			{".ctors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496a4, 0x6a4, 0x8, 0x0, 0x0, 0x4, 0x0, 0x8},
+			{".dtors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496ac, 0x6ac, 0x8, 0x0, 0x0, 0x4, 0x0, 0x8},
+			{".jcr", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496b4, 0x6b4, 0x4, 0x0, 0x0, 0x4, 0x0, 0x4},
+			{".got", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x80496b8, 0x6b8, 0x1c, 0x0, 0x0, 0x4, 0x4, 0x1c},
+			{".bss", SHT_NOBITS, SHF_WRITE + SHF_ALLOC, 0x80496d4, 0x6d4, 0x20, 0x0, 0x0, 0x4, 0x0, 0x20},
+			{".comment", SHT_PROGBITS, 0x0, 0x0, 0x6d4, 0x12d, 0x0, 0x0, 0x1, 0x0, 0x12d},
+			{".debug_aranges", SHT_PROGBITS, 0x0, 0x0, 0x801, 0x20, 0x0, 0x0, 0x1, 0x0, 0x20},
+			{".debug_pubnames", SHT_PROGBITS, 0x0, 0x0, 0x821, 0x1b, 0x0, 0x0, 0x1, 0x0, 0x1b},
+			{".debug_info", SHT_PROGBITS, 0x0, 0x0, 0x83c, 0x11d, 0x0, 0x0, 0x1, 0x0, 0x11d},
+			{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0x959, 0x41, 0x0, 0x0, 0x1, 0x0, 0x41},
+			{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0x99a, 0x35, 0x0, 0x0, 0x1, 0x0, 0x35},
+			{".debug_frame", SHT_PROGBITS, 0x0, 0x0, 0x9d0, 0x30, 0x0, 0x0, 0x4, 0x0, 0x30},
+			{".debug_str", SHT_PROGBITS, 0x0, 0x0, 0xa00, 0xd, 0x0, 0x0, 0x1, 0x0, 0xd},
+			{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0xa0d, 0xf8, 0x0, 0x0, 0x1, 0x0, 0xf8},
+			{".symtab", SHT_SYMTAB, 0x0, 0x0, 0xfb8, 0x4b0, 0x1d, 0x38, 0x4, 0x10, 0x4b0},
+			{".strtab", SHT_STRTAB, 0x0, 0x0, 0x1468, 0x206, 0x0, 0x0, 0x1, 0x0, 0x206},
 		},
 		[]ProgHeader{
 			{PT_PHDR, PF_R + PF_X, 0x34, 0x8048034, 0x8048034, 0xa0, 0xa0, 0x4},
@@ -75,43 +76,43 @@ var fileTests = []fileTest{
 		"testdata/gcc-amd64-linux-exec",
 		FileHeader{ELFCLASS64, ELFDATA2LSB, EV_CURRENT, ELFOSABI_NONE, 0, binary.LittleEndian, ET_EXEC, EM_X86_64, 0x4003e0},
 		[]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},
+			{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+			{".interp", SHT_PROGBITS, SHF_ALLOC, 0x400200, 0x200, 0x1c, 0x0, 0x0, 0x1, 0x0, 0x1c},
+			{".note.ABI-tag", SHT_NOTE, SHF_ALLOC, 0x40021c, 0x21c, 0x20, 0x0, 0x0, 0x4, 0x0, 0x20},
+			{".hash", SHT_HASH, SHF_ALLOC, 0x400240, 0x240, 0x24, 0x5, 0x0, 0x8, 0x4, 0x24},
+			{".gnu.hash", SHT_LOOS + 268435446, SHF_ALLOC, 0x400268, 0x268, 0x1c, 0x5, 0x0, 0x8, 0x0, 0x1c},
+			{".dynsym", SHT_DYNSYM, SHF_ALLOC, 0x400288, 0x288, 0x60, 0x6, 0x1, 0x8, 0x18, 0x60},
+			{".dynstr", SHT_STRTAB, SHF_ALLOC, 0x4002e8, 0x2e8, 0x3d, 0x0, 0x0, 0x1, 0x0, 0x3d},
+			{".gnu.version", SHT_HIOS, SHF_ALLOC, 0x400326, 0x326, 0x8, 0x5, 0x0, 0x2, 0x2, 0x8},
+			{".gnu.version_r", SHT_LOOS + 268435454, SHF_ALLOC, 0x400330, 0x330, 0x20, 0x6, 0x1, 0x8, 0x0, 0x20},
+			{".rela.dyn", SHT_RELA, SHF_ALLOC, 0x400350, 0x350, 0x18, 0x5, 0x0, 0x8, 0x18, 0x18},
+			{".rela.plt", SHT_RELA, SHF_ALLOC, 0x400368, 0x368, 0x30, 0x5, 0xc, 0x8, 0x18, 0x30},
+			{".init", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x400398, 0x398, 0x18, 0x0, 0x0, 0x4, 0x0, 0x18},
+			{".plt", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x4003b0, 0x3b0, 0x30, 0x0, 0x0, 0x4, 0x10, 0x30},
+			{".text", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x4003e0, 0x3e0, 0x1b4, 0x0, 0x0, 0x10, 0x0, 0x1b4},
+			{".fini", SHT_PROGBITS, SHF_ALLOC + SHF_EXECINSTR, 0x400594, 0x594, 0xe, 0x0, 0x0, 0x4, 0x0, 0xe},
+			{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x4005a4, 0x5a4, 0x11, 0x0, 0x0, 0x4, 0x0, 0x11},
+			{".eh_frame_hdr", SHT_PROGBITS, SHF_ALLOC, 0x4005b8, 0x5b8, 0x24, 0x0, 0x0, 0x4, 0x0, 0x24},
+			{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x4005e0, 0x5e0, 0xa4, 0x0, 0x0, 0x8, 0x0, 0xa4},
+			{".ctors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600688, 0x688, 0x10, 0x0, 0x0, 0x8, 0x0, 0x10},
+			{".dtors", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600698, 0x698, 0x10, 0x0, 0x0, 0x8, 0x0, 0x10},
+			{".jcr", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x6006a8, 0x6a8, 0x8, 0x0, 0x0, 0x8, 0x0, 0x8},
+			{".dynamic", SHT_DYNAMIC, SHF_WRITE + SHF_ALLOC, 0x6006b0, 0x6b0, 0x1a0, 0x6, 0x0, 0x8, 0x10, 0x1a0},
+			{".got", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600850, 0x850, 0x8, 0x0, 0x0, 0x8, 0x8, 0x8},
+			{".got.plt", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600858, 0x858, 0x28, 0x0, 0x0, 0x8, 0x8, 0x28},
+			{".data", SHT_PROGBITS, SHF_WRITE + SHF_ALLOC, 0x600880, 0x880, 0x18, 0x0, 0x0, 0x8, 0x0, 0x18},
+			{".bss", SHT_NOBITS, SHF_WRITE + SHF_ALLOC, 0x600898, 0x898, 0x8, 0x0, 0x0, 0x4, 0x0, 0x8},
+			{".comment", SHT_PROGBITS, 0x0, 0x0, 0x898, 0x126, 0x0, 0x0, 0x1, 0x0, 0x126},
+			{".debug_aranges", SHT_PROGBITS, 0x0, 0x0, 0x9c0, 0x90, 0x0, 0x0, 0x10, 0x0, 0x90},
+			{".debug_pubnames", SHT_PROGBITS, 0x0, 0x0, 0xa50, 0x25, 0x0, 0x0, 0x1, 0x0, 0x25},
+			{".debug_info", SHT_PROGBITS, 0x0, 0x0, 0xa75, 0x1a7, 0x0, 0x0, 0x1, 0x0, 0x1a7},
+			{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0xc1c, 0x6f, 0x0, 0x0, 0x1, 0x0, 0x6f},
+			{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0xc8b, 0x13f, 0x0, 0x0, 0x1, 0x0, 0x13f},
+			{".debug_str", SHT_PROGBITS, SHF_MERGE + SHF_STRINGS, 0x0, 0xdca, 0xb1, 0x0, 0x0, 0x1, 0x1, 0xb1},
+			{".debug_ranges", SHT_PROGBITS, 0x0, 0x0, 0xe80, 0x90, 0x0, 0x0, 0x10, 0x0, 0x90},
+			{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0xf10, 0x149, 0x0, 0x0, 0x1, 0x0, 0x149},
+			{".symtab", SHT_SYMTAB, 0x0, 0x0, 0x19a0, 0x6f0, 0x24, 0x39, 0x8, 0x18, 0x6f0},
+			{".strtab", SHT_STRTAB, 0x0, 0x0, 0x2090, 0x1fc, 0x0, 0x0, 0x1, 0x0, 0x1fc},
 		},
 		[]ProgHeader{
 			{PT_PHDR, PF_R + PF_X, 0x40, 0x400040, 0x400040, 0x1c0, 0x1c0, 0x8},
@@ -150,6 +151,64 @@ var fileTests = []fileTest{
 		},
 		nil,
 	},
+	{
+		"testdata/compressed-32.obj",
+		FileHeader{ELFCLASS32, ELFDATA2LSB, EV_CURRENT, ELFOSABI_NONE, 0x0, binary.LittleEndian, ET_REL, EM_386, 0x0},
+		[]SectionHeader{
+			{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+			{".text", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR, 0x0, 0x34, 0x17, 0x0, 0x0, 0x1, 0x0, 0x17},
+			{".rel.text", SHT_REL, SHF_INFO_LINK, 0x0, 0x3dc, 0x10, 0x13, 0x1, 0x4, 0x8, 0x10},
+			{".data", SHT_PROGBITS, SHF_WRITE | SHF_ALLOC, 0x0, 0x4b, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
+			{".bss", SHT_NOBITS, SHF_WRITE | SHF_ALLOC, 0x0, 0x4b, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
+			{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x0, 0x4b, 0xd, 0x0, 0x0, 0x1, 0x0, 0xd},
+			{".debug_info", SHT_PROGBITS, SHF_COMPRESSED, 0x0, 0x58, 0xb4, 0x0, 0x0, 0x1, 0x0, 0x84},
+			{".rel.debug_info", SHT_REL, SHF_INFO_LINK, 0x0, 0x3ec, 0xa0, 0x13, 0x6, 0x4, 0x8, 0xa0},
+			{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0xdc, 0x5a, 0x0, 0x0, 0x1, 0x0, 0x5a},
+			{".debug_aranges", SHT_PROGBITS, 0x0, 0x0, 0x136, 0x20, 0x0, 0x0, 0x1, 0x0, 0x20},
+			{".rel.debug_aranges", SHT_REL, SHF_INFO_LINK, 0x0, 0x48c, 0x10, 0x13, 0x9, 0x4, 0x8, 0x10},
+			{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0x156, 0x5c, 0x0, 0x0, 0x1, 0x0, 0x5c},
+			{".rel.debug_line", SHT_REL, SHF_INFO_LINK, 0x0, 0x49c, 0x8, 0x13, 0xb, 0x4, 0x8, 0x8},
+			{".debug_str", SHT_PROGBITS, SHF_MERGE | SHF_STRINGS | SHF_COMPRESSED, 0x0, 0x1b2, 0x10f, 0x0, 0x0, 0x1, 0x1, 0xb3},
+			{".comment", SHT_PROGBITS, SHF_MERGE | SHF_STRINGS, 0x0, 0x265, 0x2a, 0x0, 0x0, 0x1, 0x1, 0x2a},
+			{".note.GNU-stack", SHT_PROGBITS, 0x0, 0x0, 0x28f, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
+			{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x0, 0x290, 0x38, 0x0, 0x0, 0x4, 0x0, 0x38},
+			{".rel.eh_frame", SHT_REL, SHF_INFO_LINK, 0x0, 0x4a4, 0x8, 0x13, 0x10, 0x4, 0x8, 0x8},
+			{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0x4ac, 0xab, 0x0, 0x0, 0x1, 0x0, 0xab},
+			{".symtab", SHT_SYMTAB, 0x0, 0x0, 0x2c8, 0x100, 0x14, 0xe, 0x4, 0x10, 0x100},
+			{".strtab", SHT_STRTAB, 0x0, 0x0, 0x3c8, 0x13, 0x0, 0x0, 0x1, 0x0, 0x13},
+		},
+		[]ProgHeader{},
+		nil,
+	},
+	{
+		"testdata/compressed-64.obj",
+		FileHeader{ELFCLASS64, ELFDATA2LSB, EV_CURRENT, ELFOSABI_NONE, 0x0, binary.LittleEndian, ET_REL, EM_X86_64, 0x0},
+		[]SectionHeader{
+			{"", SHT_NULL, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+			{".text", SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR, 0x0, 0x40, 0x1b, 0x0, 0x0, 0x1, 0x0, 0x1b},
+			{".rela.text", SHT_RELA, SHF_INFO_LINK, 0x0, 0x488, 0x30, 0x13, 0x1, 0x8, 0x18, 0x30},
+			{".data", SHT_PROGBITS, SHF_WRITE | SHF_ALLOC, 0x0, 0x5b, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
+			{".bss", SHT_NOBITS, SHF_WRITE | SHF_ALLOC, 0x0, 0x5b, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
+			{".rodata", SHT_PROGBITS, SHF_ALLOC, 0x0, 0x5b, 0xd, 0x0, 0x0, 0x1, 0x0, 0xd},
+			{".debug_info", SHT_PROGBITS, SHF_COMPRESSED, 0x0, 0x68, 0xba, 0x0, 0x0, 0x1, 0x0, 0x72},
+			{".rela.debug_info", SHT_RELA, SHF_INFO_LINK, 0x0, 0x4b8, 0x1c8, 0x13, 0x6, 0x8, 0x18, 0x1c8},
+			{".debug_abbrev", SHT_PROGBITS, 0x0, 0x0, 0xda, 0x5c, 0x0, 0x0, 0x1, 0x0, 0x5c},
+			{".debug_aranges", SHT_PROGBITS, SHF_COMPRESSED, 0x0, 0x136, 0x30, 0x0, 0x0, 0x1, 0x0, 0x2f},
+			{".rela.debug_aranges", SHT_RELA, SHF_INFO_LINK, 0x0, 0x680, 0x30, 0x13, 0x9, 0x8, 0x18, 0x30},
+			{".debug_line", SHT_PROGBITS, 0x0, 0x0, 0x165, 0x60, 0x0, 0x0, 0x1, 0x0, 0x60},
+			{".rela.debug_line", SHT_RELA, SHF_INFO_LINK, 0x0, 0x6b0, 0x18, 0x13, 0xb, 0x8, 0x18, 0x18},
+			{".debug_str", SHT_PROGBITS, SHF_MERGE | SHF_STRINGS | SHF_COMPRESSED, 0x0, 0x1c5, 0x104, 0x0, 0x0, 0x1, 0x1, 0xc3},
+			{".comment", SHT_PROGBITS, SHF_MERGE | SHF_STRINGS, 0x0, 0x288, 0x2a, 0x0, 0x0, 0x1, 0x1, 0x2a},
+			{".note.GNU-stack", SHT_PROGBITS, 0x0, 0x0, 0x2b2, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0},
+			{".eh_frame", SHT_PROGBITS, SHF_ALLOC, 0x0, 0x2b8, 0x38, 0x0, 0x0, 0x8, 0x0, 0x38},
+			{".rela.eh_frame", SHT_RELA, SHF_INFO_LINK, 0x0, 0x6c8, 0x18, 0x13, 0x10, 0x8, 0x18, 0x18},
+			{".shstrtab", SHT_STRTAB, 0x0, 0x0, 0x6e0, 0xb0, 0x0, 0x0, 0x1, 0x0, 0xb0},
+			{".symtab", SHT_SYMTAB, 0x0, 0x0, 0x2f0, 0x180, 0x14, 0xe, 0x8, 0x18, 0x180},
+			{".strtab", SHT_STRTAB, 0x0, 0x0, 0x470, 0x13, 0x0, 0x0, 0x1, 0x0, 0x13},
+		},
+		[]ProgHeader{},
+		nil,
+	},
 }
 
 func TestOpen(t *testing.T) {
@@ -245,62 +304,237 @@ var relocationTests = []relocationTest{
 	{
 		"testdata/go-relocation-test-gcc441-x86-64.obj",
 		[]relocationTestEntry{
-			{0, &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.4.1", Class: dwarf.ClassString}, {Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrName, Val: "go-relocation-test.c", Class: dwarf.ClassString}, {Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress}, {Attr: dwarf.AttrHighpc, Val: uint64(0x6), Class: dwarf.ClassAddress}, {Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr}}}},
+			{0, &dwarf.Entry{
+				Offset:   0xb,
+				Tag:      dwarf.TagCompileUnit,
+				Children: true,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrProducer, Val: "GNU C 4.4.1", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrName, Val: "go-relocation-test.c", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrHighpc, Val: uint64(0x6), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr},
+				},
+			}},
 		},
 	},
 	{
 		"testdata/go-relocation-test-gcc441-x86.obj",
 		[]relocationTestEntry{
-			{0, &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.4.1", Class: dwarf.ClassString}, {Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrName, Val: "t.c", Class: dwarf.ClassString}, {Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress}, {Attr: dwarf.AttrHighpc, Val: uint64(0x5), Class: dwarf.ClassAddress}, {Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr}}}},
+			{0, &dwarf.Entry{
+				Offset:   0xb,
+				Tag:      dwarf.TagCompileUnit,
+				Children: true,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrProducer, Val: "GNU C 4.4.1", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrName, Val: "t.c", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrHighpc, Val: uint64(0x5), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr},
+				},
+			}},
 		},
 	},
 	{
 		"testdata/go-relocation-test-gcc424-x86-64.obj",
 		[]relocationTestEntry{
-			{0, &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)", Class: dwarf.ClassString}, {Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrName, Val: "go-relocation-test-gcc424.c", Class: dwarf.ClassString}, {Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress}, {Attr: dwarf.AttrHighpc, Val: uint64(0x6), Class: dwarf.ClassAddress}, {Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr}}}},
+			{0, &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)", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrName, Val: "go-relocation-test-gcc424.c", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrHighpc, Val: uint64(0x6), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr},
+				},
+			}},
 		},
 	},
 	{
 		"testdata/go-relocation-test-gcc482-aarch64.obj",
 		[]relocationTestEntry{
-			{0, &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.8.2 -g -fstack-protector", Class: dwarf.ClassString}, {Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrName, Val: "go-relocation-test-gcc482.c", Class: dwarf.ClassString}, {Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress}, {Attr: dwarf.AttrHighpc, Val: int64(0x24), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr}}}},
+			{0, &dwarf.Entry{
+				Offset:   0xb,
+				Tag:      dwarf.TagCompileUnit,
+				Children: true,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrProducer, Val: "GNU C 4.8.2 -g -fstack-protector", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrName, Val: "go-relocation-test-gcc482.c", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrHighpc, Val: int64(0x24), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr},
+				},
+			}},
 		},
 	},
 	{
 		"testdata/go-relocation-test-gcc492-arm.obj",
 		[]relocationTestEntry{
-			{0, &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.9.2 20141224 (prerelease) -march=armv7-a -mfloat-abi=hard -mfpu=vfpv3-d16 -mtls-dialect=gnu -g", Class: dwarf.ClassString}, {Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrName, Val: "go-relocation-test-gcc492.c", Class: dwarf.ClassString}, {Attr: dwarf.AttrCompDir, Val: "/root/go/src/debug/elf/testdata", Class: dwarf.ClassString}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress}, {Attr: dwarf.AttrHighpc, Val: int64(0x28), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr}}}},
+			{0, &dwarf.Entry{
+				Offset:   0xb,
+				Tag:      dwarf.TagCompileUnit,
+				Children: true,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrProducer, Val: "GNU C 4.9.2 20141224 (prerelease) -march=armv7-a -mfloat-abi=hard -mfpu=vfpv3-d16 -mtls-dialect=gnu -g", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrName, Val: "go-relocation-test-gcc492.c", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrCompDir, Val: "/root/go/src/debug/elf/testdata", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrHighpc, Val: int64(0x28), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr},
+				},
+			}},
 		},
 	},
 	{
 		"testdata/go-relocation-test-clang-arm.obj",
 		[]relocationTestEntry{
-			{0, &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{dwarf.Field{Attr: dwarf.AttrProducer, Val: "Debian clang version 3.5.0-10 (tags/RELEASE_350/final) (based on LLVM 3.5.0)", Class: dwarf.ClassString}, dwarf.Field{Attr: dwarf.AttrLanguage, Val: int64(12), Class: dwarf.ClassConstant}, dwarf.Field{Attr: dwarf.AttrName, Val: "hello.c", Class: dwarf.ClassString}, dwarf.Field{Attr: dwarf.AttrStmtList, Val: int64(0x0), Class: dwarf.ClassLinePtr}, dwarf.Field{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString}, dwarf.Field{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress}, dwarf.Field{Attr: dwarf.AttrHighpc, Val: int64(48), Class: dwarf.ClassConstant}}}},
+			{0, &dwarf.Entry{
+				Offset:   0xb,
+				Tag:      dwarf.TagCompileUnit,
+				Children: true,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrProducer, Val: "Debian clang version 3.5.0-10 (tags/RELEASE_350/final) (based on LLVM 3.5.0)", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLanguage, Val: int64(12), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrName, Val: "hello.c", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrStmtList, Val: int64(0x0), Class: dwarf.ClassLinePtr},
+					{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrHighpc, Val: int64(48), Class: dwarf.ClassConstant},
+				},
+			}},
 		},
 	},
 	{
 		"testdata/go-relocation-test-gcc5-ppc.obj",
 		[]relocationTestEntry{
-			{0, &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{dwarf.Field{Attr: dwarf.AttrProducer, Val: "GNU C11 5.0.0 20150116 (experimental) -Asystem=linux -Asystem=unix -Asystem=posix -g", Class: dwarf.ClassString}, dwarf.Field{Attr: dwarf.AttrLanguage, Val: int64(12), Class: dwarf.ClassConstant}, dwarf.Field{Attr: dwarf.AttrName, Val: "go-relocation-test-gcc5-ppc.c", Class: dwarf.ClassString}, dwarf.Field{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString}, dwarf.Field{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress}, dwarf.Field{Attr: dwarf.AttrHighpc, Val: int64(0x44), Class: dwarf.ClassConstant}, dwarf.Field{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr}}}},
+			{0, &dwarf.Entry{
+				Offset:   0xb,
+				Tag:      dwarf.TagCompileUnit,
+				Children: true,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrProducer, Val: "GNU C11 5.0.0 20150116 (experimental) -Asystem=linux -Asystem=unix -Asystem=posix -g", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLanguage, Val: int64(12), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrName, Val: "go-relocation-test-gcc5-ppc.c", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrHighpc, Val: int64(0x44), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr},
+				},
+			}},
 		},
 	},
 	{
 		"testdata/go-relocation-test-gcc482-ppc64le.obj",
 		[]relocationTestEntry{
-			{0, &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{dwarf.Field{Attr: dwarf.AttrProducer, Val: "GNU C 4.8.2 -Asystem=linux -Asystem=unix -Asystem=posix -msecure-plt -mtune=power8 -mcpu=power7 -gdwarf-2 -fstack-protector", Class: dwarf.ClassString}, dwarf.Field{Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant}, dwarf.Field{Attr: dwarf.AttrName, Val: "go-relocation-test-gcc482-ppc64le.c", Class: dwarf.ClassString}, dwarf.Field{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString}, dwarf.Field{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress}, dwarf.Field{Attr: dwarf.AttrHighpc, Val: uint64(0x24), Class: dwarf.ClassAddress}, dwarf.Field{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr}}}},
+			{0, &dwarf.Entry{
+				Offset:   0xb,
+				Tag:      dwarf.TagCompileUnit,
+				Children: true,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrProducer, Val: "GNU C 4.8.2 -Asystem=linux -Asystem=unix -Asystem=posix -msecure-plt -mtune=power8 -mcpu=power7 -gdwarf-2 -fstack-protector", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrName, Val: "go-relocation-test-gcc482-ppc64le.c", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrHighpc, Val: uint64(0x24), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr},
+				},
+			}},
+		},
+	},
+	{
+		"testdata/go-relocation-test-gcc492-mips64.obj",
+		[]relocationTestEntry{
+			{0, &dwarf.Entry{
+				Offset:   0xb,
+				Tag:      dwarf.TagCompileUnit,
+				Children: true,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrProducer, Val: "GNU C 4.9.2 -meb -mabi=64 -march=mips3 -mtune=mips64 -mllsc -mno-shared -g", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrName, Val: "hello.c", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrHighpc, Val: int64(100), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr},
+				},
+			}},
+		},
+	},
+	{
+		"testdata/go-relocation-test-gcc493-mips64le.obj",
+		[]relocationTestEntry{
+			{0, &dwarf.Entry{
+				Offset:   0xb,
+				Tag:      dwarf.TagCompileUnit,
+				Children: true,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrProducer, Val: "GNU C 4.9.3 -mel -mabi=64 -mllsc -mno-shared -g -fstack-protector-strong", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLanguage, Val: int64(1), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrName, Val: "hello.c", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLowpc, Val: uint64(0x0), Class: dwarf.ClassAddress},
+					{Attr: dwarf.AttrHighpc, Val: int64(100), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr},
+				},
+			}},
 		},
 	},
 	{
 		"testdata/go-relocation-test-clang-x86.obj",
 		[]relocationTestEntry{
-			{0, &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "clang version google3-trunk (trunk r209387)", Class: dwarf.ClassString}, {Attr: dwarf.AttrLanguage, Val: int64(12), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrName, Val: "go-relocation-test-clang.c", Class: dwarf.ClassString}, {Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr}, {Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString}}}},
+			{0, &dwarf.Entry{
+				Offset:   0xb,
+				Tag:      dwarf.TagCompileUnit,
+				Children: true,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrProducer, Val: "clang version google3-trunk (trunk r209387)", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrLanguage, Val: int64(12), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrName, Val: "go-relocation-test-clang.c", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrStmtList, Val: int64(0), Class: dwarf.ClassLinePtr},
+					{Attr: dwarf.AttrCompDir, Val: "/tmp", Class: dwarf.ClassString},
+				},
+			}},
 		},
 	},
 	{
 		"testdata/gcc-amd64-openbsd-debug-with-rela.obj",
 		[]relocationTestEntry{
-			{203, &dwarf.Entry{Offset: 0xc62, Tag: dwarf.TagMember, Children: false, Field: []dwarf.Field{{Attr: dwarf.AttrName, Val: "it_interval", Class: dwarf.ClassString}, {Attr: dwarf.AttrDeclFile, Val: int64(7), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrDeclLine, Val: int64(236), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrType, Val: dwarf.Offset(0xb7f), Class: dwarf.ClassReference}, {Attr: dwarf.AttrDataMemberLoc, Val: []byte{0x23, 0x0}, Class: dwarf.ClassExprLoc}}}},
-			{204, &dwarf.Entry{Offset: 0xc70, Tag: dwarf.TagMember, Children: false, Field: []dwarf.Field{{Attr: dwarf.AttrName, Val: "it_value", Class: dwarf.ClassString}, {Attr: dwarf.AttrDeclFile, Val: int64(7), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrDeclLine, Val: int64(237), Class: dwarf.ClassConstant}, {Attr: dwarf.AttrType, Val: dwarf.Offset(0xb7f), Class: dwarf.ClassReference}, {Attr: dwarf.AttrDataMemberLoc, Val: []byte{0x23, 0x10}, Class: dwarf.ClassExprLoc}}}},
+			{203, &dwarf.Entry{
+				Offset:   0xc62,
+				Tag:      dwarf.TagMember,
+				Children: false,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrName, Val: "it_interval", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrDeclFile, Val: int64(7), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrDeclLine, Val: int64(236), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrType, Val: dwarf.Offset(0xb7f), Class: dwarf.ClassReference},
+					{Attr: dwarf.AttrDataMemberLoc, Val: []byte{0x23, 0x0}, Class: dwarf.ClassExprLoc},
+				},
+			}},
+			{204, &dwarf.Entry{
+				Offset:   0xc70,
+				Tag:      dwarf.TagMember,
+				Children: false,
+				Field: []dwarf.Field{
+					{Attr: dwarf.AttrName, Val: "it_value", Class: dwarf.ClassString},
+					{Attr: dwarf.AttrDeclFile, Val: int64(7), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrDeclLine, Val: int64(237), Class: dwarf.ClassConstant},
+					{Attr: dwarf.AttrType, Val: dwarf.Offset(0xb7f), Class: dwarf.ClassReference},
+					{Attr: dwarf.AttrDataMemberLoc, Val: []byte{0x23, 0x10}, Class: dwarf.ClassExprLoc},
+				},
+			}},
 		},
 	},
 }
@@ -339,6 +573,119 @@ func TestDWARFRelocations(t *testing.T) {
 	}
 }
 
+func TestCompressedDWARF(t *testing.T) {
+	// Test file built with GCC 4.8.4 and as 2.24 using:
+	// gcc -Wa,--compress-debug-sections -g -c -o zdebug-test-gcc484-x86-64.obj hello.c
+	f, err := Open("testdata/zdebug-test-gcc484-x86-64.obj")
+	if err != nil {
+		t.Fatal(err)
+	}
+	dwarf, err := f.DWARF()
+	if err != nil {
+		t.Fatal(err)
+	}
+	reader := dwarf.Reader()
+	n := 0
+	for {
+		entry, err := reader.Next()
+		if err != nil {
+			t.Fatal(err)
+		}
+		if entry == nil {
+			break
+		}
+		n++
+	}
+	if n != 18 {
+		t.Fatalf("want %d DWARF entries, got %d", 18, n)
+	}
+}
+
+func TestCompressedSection(t *testing.T) {
+	// Test files built with gcc -g -S hello.c and assembled with
+	// --compress-debug-sections=zlib-gabi.
+	f, err := Open("testdata/compressed-64.obj")
+	if err != nil {
+		t.Fatal(err)
+	}
+	sec := f.Section(".debug_info")
+	wantData := []byte{
+		182, 0, 0, 0, 4, 0, 0, 0, 0, 0, 8, 1, 0, 0, 0, 0,
+		1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		0, 27, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 8, 7,
+		0, 0, 0, 0, 2, 1, 8, 0, 0, 0, 0, 2, 2, 7, 0, 0,
+		0, 0, 2, 4, 7, 0, 0, 0, 0, 2, 1, 6, 0, 0, 0, 0,
+		2, 2, 5, 0, 0, 0, 0, 3, 4, 5, 105, 110, 116, 0, 2, 8,
+		5, 0, 0, 0, 0, 2, 8, 7, 0, 0, 0, 0, 4, 8, 114, 0,
+		0, 0, 2, 1, 6, 0, 0, 0, 0, 5, 0, 0, 0, 0, 1, 4,
+		0, 0, 0, 0, 0, 0, 0, 0, 27, 0, 0, 0, 0, 0, 0, 0,
+		1, 156, 179, 0, 0, 0, 6, 0, 0, 0, 0, 1, 4, 87, 0, 0,
+		0, 2, 145, 108, 6, 0, 0, 0, 0, 1, 4, 179, 0, 0, 0, 2,
+		145, 96, 0, 4, 8, 108, 0, 0, 0, 0,
+	}
+
+	// Test Data method.
+	b, err := sec.Data()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !bytes.Equal(wantData, b) {
+		t.Fatalf("want data %x, got %x", wantData, b)
+	}
+
+	// Test Open method and seeking.
+	buf, have, count := make([]byte, len(b)), make([]bool, len(b)), 0
+	sf := sec.Open()
+	if got, err := sf.Seek(0, 2); got != int64(len(b)) || err != nil {
+		t.Fatalf("want seek end %d, got %d error %v", len(b), got, err)
+	}
+	if n, err := sf.Read(buf); n != 0 || err != io.EOF {
+		t.Fatalf("want EOF with 0 bytes, got %v with %d bytes", err, n)
+	}
+	pos := int64(len(buf))
+	for count < len(buf) {
+		// Construct random seek arguments.
+		whence := rand.Intn(3)
+		target := rand.Int63n(int64(len(buf)))
+		var offset int64
+		switch whence {
+		case 0:
+			offset = target
+		case 1:
+			offset = target - pos
+		case 2:
+			offset = target - int64(len(buf))
+		}
+		pos, err = sf.Seek(offset, whence)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if pos != target {
+			t.Fatalf("want position %d, got %d", target, pos)
+		}
+
+		// Read data from the new position.
+		end := pos + 16
+		if end > int64(len(buf)) {
+			end = int64(len(buf))
+		}
+		n, err := sf.Read(buf[pos:end])
+		if err != nil {
+			t.Fatal(err)
+		}
+		for i := 0; i < n; i++ {
+			if !have[pos] {
+				have[pos] = true
+				count++
+			}
+			pos++
+		}
+	}
+	if !bytes.Equal(wantData, buf) {
+		t.Fatalf("want data %x, got %x", wantData, buf)
+	}
+}
+
 func TestNoSectionOverlaps(t *testing.T) {
 	// Ensure 6l outputs sections without overlaps.
 	if runtime.GOOS != "linux" && runtime.GOOS != "freebsd" {
diff --git a/libgo/go/debug/elf/reader.go b/libgo/go/debug/elf/reader.go
new file mode 100644
index 0000000..17b5716
--- /dev/null
+++ b/libgo/go/debug/elf/reader.go
@@ -0,0 +1,108 @@
+// Copyright 2015 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package elf
+
+import (
+	"io"
+	"os"
+)
+
+// errorReader returns error from all operations.
+type errorReader struct {
+	error
+}
+
+func (r errorReader) Read(p []byte) (n int, err error) {
+	return 0, r.error
+}
+
+func (r errorReader) ReadAt(p []byte, off int64) (n int, err error) {
+	return 0, r.error
+}
+
+func (r errorReader) Seek(offset int64, whence int) (int64, error) {
+	return 0, r.error
+}
+
+func (r errorReader) Close() error {
+	return r.error
+}
+
+// readSeekerFromReader converts an io.Reader into an io.ReadSeeker.
+// In general Seek may not be efficient, but it is optimized for
+// common cases such as seeking to the end to find the length of the
+// data.
+type readSeekerFromReader struct {
+	reset  func() (io.Reader, error)
+	r      io.Reader
+	size   int64
+	offset int64
+}
+
+func (r *readSeekerFromReader) start() {
+	x, err := r.reset()
+	if err != nil {
+		r.r = errorReader{err}
+	} else {
+		r.r = x
+	}
+	r.offset = 0
+}
+
+func (r *readSeekerFromReader) Read(p []byte) (n int, err error) {
+	if r.r == nil {
+		r.start()
+	}
+	n, err = r.r.Read(p)
+	r.offset += int64(n)
+	return n, err
+}
+
+func (r *readSeekerFromReader) Seek(offset int64, whence int) (int64, error) {
+	var newOffset int64
+	switch whence {
+	case 0:
+		newOffset = offset
+	case 1:
+		newOffset = r.offset + offset
+	case 2:
+		newOffset = r.size + offset
+	default:
+		return 0, os.ErrInvalid
+	}
+
+	switch {
+	case newOffset == r.offset:
+		return newOffset, nil
+
+	case newOffset < 0, newOffset > r.size:
+		return 0, os.ErrInvalid
+
+	case newOffset == 0:
+		r.r = nil
+
+	case newOffset == r.size:
+		r.r = errorReader{io.EOF}
+
+	default:
+		if newOffset < r.offset {
+			// Restart at the beginning.
+			r.start()
+		}
+		// Read until we reach offset.
+		var buf [512]byte
+		for r.offset < newOffset {
+			b := buf[:]
+			if newOffset-r.offset < int64(len(buf)) {
+				b = buf[:newOffset-r.offset]
+			}
+			if _, err := r.Read(b); err != nil {
+				return 0, err
+			}
+		}
+	}
+	r.offset = newOffset
+	return r.offset, nil
+}
diff --git a/libgo/go/debug/elf/testdata/compressed-32.obj b/libgo/go/debug/elf/testdata/compressed-32.obj
new file mode 100644
index 0000000..2bfdb44
--- /dev/null
+++ b/libgo/go/debug/elf/testdata/compressed-32.obj
diff --git a/libgo/go/debug/elf/testdata/compressed-64.obj b/libgo/go/debug/elf/testdata/compressed-64.obj
new file mode 100644
index 0000000..ffae56a
--- /dev/null
+++ b/libgo/go/debug/elf/testdata/compressed-64.obj
diff --git a/libgo/go/debug/elf/testdata/go-relocation-test-gcc492-mips64.obj b/libgo/go/debug/elf/testdata/go-relocation-test-gcc492-mips64.obj
new file mode 100644
index 0000000..68febe1
--- /dev/null
+++ b/libgo/go/debug/elf/testdata/go-relocation-test-gcc492-mips64.obj
diff --git a/libgo/go/debug/elf/testdata/go-relocation-test-gcc493-mips64le.obj b/libgo/go/debug/elf/testdata/go-relocation-test-gcc493-mips64le.obj
new file mode 100644
index 0000000..20bbd6c
--- /dev/null
+++ b/libgo/go/debug/elf/testdata/go-relocation-test-gcc493-mips64le.obj
diff --git a/libgo/go/debug/elf/testdata/zdebug-test-gcc484-x86-64.obj b/libgo/go/debug/elf/testdata/zdebug-test-gcc484-x86-64.obj
new file mode 100644
index 0000000..a595a01
--- /dev/null
+++ b/libgo/go/debug/elf/testdata/zdebug-test-gcc484-x86-64.obj
diff --git a/libgo/go/debug/gosym/pclntab_test.go b/libgo/go/debug/gosym/pclntab_test.go
index 53f3e95..8d4aa54 100644
--- a/libgo/go/debug/gosym/pclntab_test.go
+++ b/libgo/go/debug/gosym/pclntab_test.go
@@ -6,6 +6,7 @@ package gosym
 
 import (
 	"debug/elf"
+	"internal/testenv"
 	"io/ioutil"
 	"os"
 	"os/exec"
@@ -20,25 +21,16 @@ var (
 	pclinetestBinary string
 )
 
-func dotest(self bool) bool {
+func dotest(t *testing.T) {
+	testenv.MustHaveGoBuild(t)
 	// For now, only works on amd64 platforms.
 	if runtime.GOARCH != "amd64" {
-		return false
-	}
-	// Self test reads test binary; only works on Linux.
-	if self && runtime.GOOS != "linux" {
-		return false
-	}
-	if pclinetestBinary != "" {
-		return true
+		t.Skipf("skipping on non-AMD64 system %s", runtime.GOARCH)
 	}
 	var err error
 	pclineTempDir, err = ioutil.TempDir("", "pclinetest")
 	if err != nil {
-		panic(err)
-	}
-	if strings.Contains(pclineTempDir, " ") {
-		panic("unexpected space in tempdir")
+		t.Fatal(err)
 	}
 	// This command builds pclinetest from pclinetest.asm;
 	// the resulting binary looks like it was built from pclinetest.s,
@@ -48,16 +40,15 @@ func dotest(self bool) bool {
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	if err := cmd.Run(); err != nil {
-		panic(err)
+		t.Fatal(err)
 	}
 	cmd = exec.Command("go", "tool", "link", "-H", "linux", "-E", "main",
 		"-o", pclinetestBinary, pclinetestBinary+".o")
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	if err := cmd.Run(); err != nil {
-		panic(err)
+		t.Fatal(err)
 	}
-	return true
 }
 
 func endtest() {
@@ -68,6 +59,17 @@ func endtest() {
 	}
 }
 
+// skipIfNotELF skips the test if we are not running on an ELF system.
+// These tests open and examine the test binary, and use elf.Open to do so.
+func skipIfNotELF(t *testing.T) {
+	switch runtime.GOOS {
+	case "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "solaris":
+		// OK.
+	default:
+		t.Skipf("skipping on non-ELF system %s", runtime.GOOS)
+	}
+}
+
 func getTable(t *testing.T) *Table {
 	f, tab := crack(os.Args[0], t)
 	f.Close()
@@ -112,10 +114,7 @@ func parse(file string, f *elf.File, t *testing.T) (*elf.File, *Table) {
 var goarch = os.Getenv("O")
 
 func TestLineFromAline(t *testing.T) {
-	if !dotest(true) {
-		return
-	}
-	defer endtest()
+	skipIfNotELF(t)
 
 	tab := getTable(t)
 	if tab.go12line != nil {
@@ -164,10 +163,7 @@ func TestLineFromAline(t *testing.T) {
 }
 
 func TestLineAline(t *testing.T) {
-	if !dotest(true) {
-		return
-	}
-	defer endtest()
+	skipIfNotELF(t)
 
 	tab := getTable(t)
 	if tab.go12line != nil {
@@ -210,9 +206,7 @@ func TestLineAline(t *testing.T) {
 }
 
 func TestPCLine(t *testing.T) {
-	if !dotest(false) {
-		return
-	}
+	dotest(t)
 	defer endtest()
 
 	f, tab := crack(pclinetestBinary, t)