File size: 3,840 Bytes
d7a5f2f | 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 | // Copyright 2018 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.
// Parsing of XCOFF executable (AIX)
package objfile
import (
"debug/dwarf"
"fmt"
"internal/xcoff"
"io"
"unicode"
)
type xcoffFile struct {
xcoff *xcoff.File
}
func openXcoff(r io.ReaderAt) (rawFile, error) {
f, err := xcoff.NewFile(r)
if err != nil {
return nil, err
}
return &xcoffFile{f}, nil
}
func (f *xcoffFile) symbols() ([]Sym, error) {
var syms []Sym
for _, s := range f.xcoff.Symbols {
const (
N_UNDEF = 0 // An undefined (extern) symbol
N_ABS = -1 // An absolute symbol (e_value is a constant, not an address)
N_DEBUG = -2 // A debugging symbol
)
sym := Sym{Name: s.Name, Addr: s.Value, Code: '?'}
switch s.SectionNumber {
case N_UNDEF:
sym.Code = 'U'
case N_ABS:
sym.Code = 'C'
case N_DEBUG:
sym.Code = '?'
default:
if s.SectionNumber < 0 || len(f.xcoff.Sections) < s.SectionNumber {
return nil, fmt.Errorf("invalid section number in symbol table")
}
sect := f.xcoff.Sections[s.SectionNumber-1]
// debug/xcoff returns an offset in the section not the actual address
sym.Addr += sect.VirtualAddress
if s.AuxCSect.SymbolType&0x3 == xcoff.XTY_LD {
// The size of a function is contained in the
// AUX_FCN entry
sym.Size = s.AuxFcn.Size
} else {
sym.Size = s.AuxCSect.Length
}
sym.Size = s.AuxCSect.Length
switch sect.Type {
case xcoff.STYP_TEXT:
if s.AuxCSect.StorageMappingClass == xcoff.XMC_RO {
sym.Code = 'R'
} else {
sym.Code = 'T'
}
case xcoff.STYP_DATA:
sym.Code = 'D'
case xcoff.STYP_BSS:
sym.Code = 'B'
}
if s.StorageClass == xcoff.C_HIDEXT {
// Local symbol
sym.Code = unicode.ToLower(sym.Code)
}
}
syms = append(syms, sym)
}
return syms, nil
}
func (f *xcoffFile) pcln() (textStart uint64, pclntab []byte, err error) {
if sect := f.xcoff.Section(".text"); sect != nil {
textStart = sect.VirtualAddress
}
if pclntab, err = loadXCOFFTable(f.xcoff, "runtime.pclntab", "runtime.epclntab"); err != nil {
return 0, nil, err
}
return textStart, pclntab, nil
}
func (f *xcoffFile) text() (textStart uint64, text []byte, err error) {
sect := f.xcoff.Section(".text")
if sect == nil {
return 0, nil, fmt.Errorf("text section not found")
}
textStart = sect.VirtualAddress
text, err = sect.Data()
return
}
func findXCOFFSymbol(f *xcoff.File, name string) (*xcoff.Symbol, error) {
for _, s := range f.Symbols {
if s.Name != name {
continue
}
if s.SectionNumber <= 0 {
return nil, fmt.Errorf("symbol %s: invalid section number %d", name, s.SectionNumber)
}
if len(f.Sections) < s.SectionNumber {
return nil, fmt.Errorf("symbol %s: section number %d is larger than max %d", name, s.SectionNumber, len(f.Sections))
}
return s, nil
}
return nil, fmt.Errorf("no %s symbol found", name)
}
func loadXCOFFTable(f *xcoff.File, sname, ename string) ([]byte, error) {
ssym, err := findXCOFFSymbol(f, sname)
if err != nil {
return nil, err
}
esym, err := findXCOFFSymbol(f, ename)
if err != nil {
return nil, err
}
if ssym.SectionNumber != esym.SectionNumber {
return nil, fmt.Errorf("%s and %s symbols must be in the same section", sname, ename)
}
sect := f.Sections[ssym.SectionNumber-1]
data, err := sect.Data()
if err != nil {
return nil, err
}
return data[ssym.Value:esym.Value], nil
}
func (f *xcoffFile) goarch() string {
switch f.xcoff.TargetMachine {
case xcoff.U802TOCMAGIC:
return "ppc"
case xcoff.U64_TOCMAGIC:
return "ppc64"
}
return ""
}
func (f *xcoffFile) loadAddress() (uint64, error) {
return 0, fmt.Errorf("unknown load address")
}
func (f *xcoffFile) dwarf() (*dwarf.Data, error) {
return f.xcoff.DWARF()
}
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