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// 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 "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
asize int
vers int
is64 bool // True for 64-bit DWARF format
}
// Implement the dataFormat interface.
func (u *unit) version() int {
return u.vers
}
func (u *unit) dwarf64() (bool, bool) {
return u.is64, true
}
func (u *unit) addrsize() int {
return u.asize
}
func (d *Data) parseUnits() ([]unit, error) {
// Count units.
nunit := 0
b := makeBuf(d, unknownFormat{}, "info", 0, d.info)
for len(b.data) > 0 {
len := b.uint32()
if len == 0xffffffff {
len64 := b.uint64()
if len64 != uint64(uint32(len64)) {
b.error("unit length overflow")
break
}
len = uint32(len64)
}
b.skip(int(len))
nunit++
}
if b.err != nil {
return nil, b.err
}
// Again, this time writing them down.
b = makeBuf(d, unknownFormat{}, "info", 0, d.info)
units := make([]unit, nunit)
for i := range units {
u := &units[i]
u.base = b.off
n := b.uint32()
if n == 0xffffffff {
u.is64 = true
n = uint32(b.uint64())
}
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())
if err != nil {
if b.err == nil {
b.err = err
}
break
}
u.atable = atable
u.asize = 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
}
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