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debug/dwarf: support 64-bit DWARF in byte order check

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Also fix 64-bit DWARF to read a 64-bit abbrev offset in the
compilation unit.

Change-Id: Idc22e59ffb354d58e9973b62fdbd342acf695859
Reviewed-on: https://go-review.googlesource.com/71171
Reviewed-by: Austin Clements <austin@google.com>
This commit is contained in:
Ian Lance Taylor 2017-10-16 11:11:34 -07:00
parent 4fe43f8146
commit 151c66b59f
5 changed files with 87 additions and 16 deletions
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4
src/debug/dwarf/entry.go
View File

@ -33,13 +33,13 @@ 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, vers int) (abbrevTable, error) {
func (d *Data) parseAbbrev(off uint64, vers int) (abbrevTable, error) {
if m, ok := d.abbrevCache[off]; ok {
return m, nil
}
data := d.abbrev
if off > uint32(len(data)) {
if off > uint64(len(data)) {
data = nil
} else {
data = data[off:]

60
src/debug/dwarf/entry_test.go
View File

@ -135,3 +135,63 @@ func TestReaderRanges(t *testing.T) {
t.Errorf("saw only %d subprograms, expected %d", i, len(subprograms))
}
}
func Test64Bit(t *testing.T) {
// I don't know how to generate a 64-bit DWARF debug
// compilation unit except by using XCOFF, so this is
// hand-written.
tests := []struct {
name string
info []byte
}{
{
"32-bit little",
[]byte{0x30, 0, 0, 0, // comp unit length
4, 0, // DWARF version 4
0, 0, 0, 0, // abbrev offset
8, // address size
0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
},
},
{
"64-bit little",
[]byte{0xff, 0xff, 0xff, 0xff, // 64-bit DWARF
0x30, 0, 0, 0, 0, 0, 0, 0, // comp unit length
4, 0, // DWARF version 4
0, 0, 0, 0, 0, 0, 0, 0, // abbrev offset
8, // address size
0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
},
},
{
"64-bit big",
[]byte{0xff, 0xff, 0xff, 0xff, // 64-bit DWARF
0, 0, 0, 0, 0, 0, 0, 0x30, // comp unit length
0, 4, // DWARF version 4
0, 0, 0, 0, 0, 0, 0, 0, // abbrev offset
8, // address size
0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
},
},
}
for _, test := range tests {
_, err := New(nil, nil, nil, test.info, nil, nil, nil, nil)
if err != nil {
t.Errorf("%s: %v", test.name, err)
}
}
}

17
src/debug/dwarf/open.go
View File

@ -23,7 +23,7 @@ type Data struct {
str []byte
// parsed data
abbrevCache map[uint32]abbrevTable
abbrevCache map[uint64]abbrevTable
order binary.ByteOrder
typeCache map[Offset]Type
typeSigs map[uint64]*typeUnit
@ -48,17 +48,26 @@ func New(abbrev, aranges, frame, info, line, pubnames, ranges, str []byte) (*Dat
pubnames: pubnames,
ranges: ranges,
str: str,
abbrevCache: make(map[uint32]abbrevTable),
abbrevCache: make(map[uint64]abbrevTable),
typeCache: make(map[Offset]Type),
typeSigs: make(map[uint64]*typeUnit),
}
// Sniff .debug_info to figure out byte order.
// bytes 4:6 are the version, a tiny 16-bit number (1, 2, 3).
// 32-bit DWARF: 4 byte length, 2 byte version.
// 64-bit DWARf: 4 bytes of 0xff, 8 byte length, 2 byte version.
if len(d.info) < 6 {
return nil, DecodeError{"info", Offset(len(d.info)), "too short"}
}
x, y := d.info[4], d.info[5]
offset := 4
if d.info[0] == 0xff && d.info[1] == 0xff && d.info[2] == 0xff && d.info[3] == 0xff {
if len(d.info) < 14 {
return nil, DecodeError{"info", Offset(len(d.info)), "too short"}
}
offset = 12
}
// Fetch the version, a tiny 16-bit number (1, 2, 3, 4, 5).
x, y := d.info[offset], d.info[offset+1]
switch {
case x == 0 && y == 0:
return nil, DecodeError{"info", 4, "unsupported version 0"}

11
src/debug/dwarf/typeunit.go
View File

@ -38,16 +38,11 @@ func (d *Data) parseTypes(name string, types []byte) error {
b.error("unsupported DWARF version " + strconv.Itoa(vers))
return b.err
}
var ao uint32
var ao uint64
if !dwarf64 {
ao = b.uint32()
ao = uint64(b.uint32())
} else {
ao64 := b.uint64()
if ao64 != uint64(uint32(ao64)) {
b.error("type unit abbrev offset overflow")
return b.err
}
ao = uint32(ao64)
ao = b.uint64()
}
atable, err := d.parseAbbrev(ao, vers)
if err != nil {

11
src/debug/dwarf/unit.go
View File

@ -61,13 +61,20 @@ func (d *Data) parseUnits() ([]unit, error) {
u.base = b.off
var n Offset
n, u.is64 = b.unitLength()
dataOff := b.off
vers := b.uint16()
if vers != 2 && vers != 3 && vers != 4 {
b.error("unsupported DWARF version " + strconv.Itoa(int(vers)))
break
}
u.vers = int(vers)
atable, err := d.parseAbbrev(b.uint32(), u.vers)
var abbrevOff uint64
if u.is64 {
abbrevOff = b.uint64()
} else {
abbrevOff = uint64(b.uint32())
}
atable, err := d.parseAbbrev(abbrevOff, u.vers)
if err != nil {
if b.err == nil {
b.err = err
@ -77,7 +84,7 @@ func (d *Data) parseUnits() ([]unit, error) {
u.atable = atable
u.asize = int(b.uint8())
u.off = b.off
u.data = b.bytes(int(n - (2 + 4 + 1)))
u.data = b.bytes(int(n - (b.off - dataOff)))
}
if b.err != nil {
return nil, b.err