File size: 4,215 Bytes
e36aeda | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 | // 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 (
"sort"
"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
*unit5 // info specific to DWARF 5 units
asize int
vers int
is64 bool // True for 64-bit DWARF format
utype uint8 // DWARF 5 unit type
}
type unit5 struct {
addrBase uint64
strOffsetsBase uint64
rngListsBase uint64
locListsBase uint64
}
// 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 (u *unit) addrBase() uint64 {
if u.unit5 != nil {
return u.unit5.addrBase
}
return 0
}
func (u *unit) strOffsetsBase() uint64 {
if u.unit5 != nil {
return u.unit5.strOffsetsBase
}
return 0
}
func (u *unit) rngListsBase() uint64 {
if u.unit5 != nil {
return u.unit5.rngListsBase
}
return 0
}
func (u *unit) locListsBase() uint64 {
if u.unit5 != nil {
return u.unit5.locListsBase
}
return 0
}
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.unitLength()
if len != Offset(uint32(len)) {
b.error("unit length overflow")
break
}
b.skip(int(len))
if len > 0 {
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
var n Offset
if b.err != nil {
return nil, b.err
}
for n == 0 {
n, u.is64 = b.unitLength()
}
dataOff := b.off
vers := b.uint16()
if vers < 2 || vers > 5 {
b.error("unsupported DWARF version " + strconv.Itoa(int(vers)))
break
}
u.vers = int(vers)
if vers >= 5 {
u.utype = b.uint8()
u.asize = int(b.uint8())
}
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
}
break
}
u.atable = atable
if vers < 5 {
u.asize = int(b.uint8())
}
switch u.utype {
case utSkeleton, utSplitCompile:
b.uint64() // unit ID
case utType, utSplitType:
b.uint64() // type signature
if u.is64 { // type offset
b.uint64()
} else {
b.uint32()
}
}
u.off = b.off
u.data = b.bytes(int(n - (b.off - dataOff)))
}
if b.err != nil {
return nil, b.err
}
return units, nil
}
// offsetToUnit returns the index of the unit containing offset off.
// It returns -1 if no unit contains this offset.
func (d *Data) offsetToUnit(off Offset) int {
// Find the unit after off
next := sort.Search(len(d.unit), func(i int) bool {
return d.unit[i].off > off
})
if next == 0 {
return -1
}
u := &d.unit[next-1]
if u.off <= off && off < u.off+Offset(len(u.data)) {
return next - 1
}
return -1
}
func (d *Data) collectDwarf5BaseOffsets(u *unit) error {
if u.unit5 == nil {
panic("expected unit5 to be set up already")
}
b := makeBuf(d, u, "info", u.off, u.data)
cu := b.entry(nil, u)
if cu == nil {
// Unknown abbreviation table entry or some other fatal
// problem; bail early on the assumption that this will be
// detected at some later point.
return b.err
}
if iAddrBase, ok := cu.Val(AttrAddrBase).(int64); ok {
u.unit5.addrBase = uint64(iAddrBase)
}
if iStrOffsetsBase, ok := cu.Val(AttrStrOffsetsBase).(int64); ok {
u.unit5.strOffsetsBase = uint64(iStrOffsetsBase)
}
if iRngListsBase, ok := cu.Val(AttrRnglistsBase).(int64); ok {
u.unit5.rngListsBase = uint64(iRngListsBase)
}
if iLocListsBase, ok := cu.Val(AttrLoclistsBase).(int64); ok {
u.unit5.locListsBase = uint64(iLocListsBase)
}
return nil
}
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