blob: 547b8264950f45f50a61e1ed424044648bde8026 [file] [log] [blame]
// Copyright 2019 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.
// This package defines the Go object file format, and provide "low-level" functions
// for reading and writing object files.
// The object file is understood by the compiler, assembler, linker, and tools. They
// have "high level" code that operates on object files, handling application-specific
// logics, and use this package for the actual reading and writing. Specifically, the
// code below:
//
// - cmd/internal/obj/objfile.go (used by cmd/asm and cmd/compile)
// - cmd/internal/objfile/goobj.go (used cmd/nm, cmd/objdump)
// - cmd/link/internal/loader package (used by cmd/link)
//
// If the object file format changes, they may (or may not) need to change.
package goobj
import (
"cmd/internal/bio"
"encoding/binary"
"errors"
"fmt"
"internal/unsafeheader"
"unsafe"
)
// New object file format.
//
// Header struct {
// Magic [...]byte // "\x00go120ld"
// Fingerprint [8]byte
// Flags uint32
// Offsets [...]uint32 // byte offset of each block below
// }
//
// Strings [...]struct {
// Data [...]byte
// }
//
// Autolib [...]struct { // imported packages (for file loading)
// Pkg string
// Fingerprint [8]byte
// }
//
// PkgIndex [...]string // referenced packages by index
//
// Files [...]string
//
// SymbolDefs [...]struct {
// Name string
// ABI uint16
// Type uint8
// Flag uint8
// Flag2 uint8
// Size uint32
// }
// Hashed64Defs [...]struct { // short hashed (content-addressable) symbol definitions
// ... // same as SymbolDefs
// }
// HashedDefs [...]struct { // hashed (content-addressable) symbol definitions
// ... // same as SymbolDefs
// }
// NonPkgDefs [...]struct { // non-pkg symbol definitions
// ... // same as SymbolDefs
// }
// NonPkgRefs [...]struct { // non-pkg symbol references
// ... // same as SymbolDefs
// }
//
// RefFlags [...]struct { // referenced symbol flags
// Sym symRef
// Flag uint8
// Flag2 uint8
// }
//
// Hash64 [...][8]byte
// Hash [...][N]byte
//
// RelocIndex [...]uint32 // index to Relocs
// AuxIndex [...]uint32 // index to Aux
// DataIndex [...]uint32 // offset to Data
//
// Relocs [...]struct {
// Off int32
// Size uint8
// Type uint16
// Add int64
// Sym symRef
// }
//
// Aux [...]struct {
// Type uint8
// Sym symRef
// }
//
// Data [...]byte
//
// // blocks only used by tools (objdump, nm)
//
// RefNames [...]struct { // referenced symbol names
// Sym symRef
// Name string
// // TODO: include ABI version as well?
// }
//
// string is encoded as is a uint32 length followed by a uint32 offset
// that points to the corresponding string bytes.
//
// symRef is struct { PkgIdx, SymIdx uint32 }.
//
// Slice type (e.g. []symRef) is encoded as a length prefix (uint32)
// followed by that number of elements.
//
// The types below correspond to the encoded data structure in the
// object file.
// Symbol indexing.
//
// Each symbol is referenced with a pair of indices, { PkgIdx, SymIdx },
// as the symRef struct above.
//
// PkgIdx is either a predeclared index (see PkgIdxNone below) or
// an index of an imported package. For the latter case, PkgIdx is the
// index of the package in the PkgIndex array. 0 is an invalid index.
//
// SymIdx is the index of the symbol in the given package.
// - If PkgIdx is PkgIdxSelf, SymIdx is the index of the symbol in the
// SymbolDefs array.
// - If PkgIdx is PkgIdxHashed64, SymIdx is the index of the symbol in the
// Hashed64Defs array.
// - If PkgIdx is PkgIdxHashed, SymIdx is the index of the symbol in the
// HashedDefs array.
// - If PkgIdx is PkgIdxNone, SymIdx is the index of the symbol in the
// NonPkgDefs array (could naturally overflow to NonPkgRefs array).
// - Otherwise, SymIdx is the index of the symbol in some other package's
// SymbolDefs array.
//
// {0, 0} represents a nil symbol. Otherwise PkgIdx should not be 0.
//
// Hash contains the content hashes of content-addressable symbols, of
// which PkgIdx is PkgIdxHashed, in the same order of HashedDefs array.
// Hash64 is similar, for PkgIdxHashed64 symbols.
//
// RelocIndex, AuxIndex, and DataIndex contains indices/offsets to
// Relocs/Aux/Data blocks, one element per symbol, first for all the
// defined symbols, then all the defined hashed and non-package symbols,
// in the same order of SymbolDefs/Hashed64Defs/HashedDefs/NonPkgDefs
// arrays. For N total defined symbols, the array is of length N+1. The
// last element is the total number of relocations (aux symbols, data
// blocks, etc.).
//
// They can be accessed by index. For the i-th symbol, its relocations
// are the RelocIndex[i]-th (inclusive) to RelocIndex[i+1]-th (exclusive)
// elements in the Relocs array. Aux/Data are likewise. (The index is
// 0-based.)
// Auxiliary symbols.
//
// Each symbol may (or may not) be associated with a number of auxiliary
// symbols. They are described in the Aux block. See Aux struct below.
// Currently a symbol's Gotype, FuncInfo, and associated DWARF symbols
// are auxiliary symbols.
const stringRefSize = 8 // two uint32s
type FingerprintType [8]byte
func (fp FingerprintType) IsZero() bool { return fp == FingerprintType{} }
// Package Index.
const (
PkgIdxNone = (1<<31 - 1) - iota // Non-package symbols
PkgIdxHashed64 // Short hashed (content-addressable) symbols
PkgIdxHashed // Hashed (content-addressable) symbols
PkgIdxBuiltin // Predefined runtime symbols (ex: runtime.newobject)
PkgIdxSelf // Symbols defined in the current package
PkgIdxSpecial = PkgIdxSelf // Indices above it has special meanings
PkgIdxInvalid = 0
// The index of other referenced packages starts from 1.
)
// Blocks
const (
BlkAutolib = iota
BlkPkgIdx
BlkFile
BlkSymdef
BlkHashed64def
BlkHasheddef
BlkNonpkgdef
BlkNonpkgref
BlkRefFlags
BlkHash64
BlkHash
BlkRelocIdx
BlkAuxIdx
BlkDataIdx
BlkReloc
BlkAux
BlkData
BlkRefName
BlkEnd
NBlk
)
// File header.
// TODO: probably no need to export this.
type Header struct {
Magic string
Fingerprint FingerprintType
Flags uint32
Offsets [NBlk]uint32
}
const Magic = "\x00go120ld"
func (h *Header) Write(w *Writer) {
w.RawString(h.Magic)
w.Bytes(h.Fingerprint[:])
w.Uint32(h.Flags)
for _, x := range h.Offsets {
w.Uint32(x)
}
}
func (h *Header) Read(r *Reader) error {
b := r.BytesAt(0, len(Magic))
h.Magic = string(b)
if h.Magic != Magic {
return errors.New("wrong magic, not a Go object file")
}
off := uint32(len(h.Magic))
copy(h.Fingerprint[:], r.BytesAt(off, len(h.Fingerprint)))
off += 8
h.Flags = r.uint32At(off)
off += 4
for i := range h.Offsets {
h.Offsets[i] = r.uint32At(off)
off += 4
}
return nil
}
func (h *Header) Size() int {
return len(h.Magic) + 4 + 4*len(h.Offsets)
}
// Autolib
type ImportedPkg struct {
Pkg string
Fingerprint FingerprintType
}
const importedPkgSize = stringRefSize + 8
func (p *ImportedPkg) Write(w *Writer) {
w.StringRef(p.Pkg)
w.Bytes(p.Fingerprint[:])
}
// Symbol definition.
//
// Serialized format:
//
// Sym struct {
// Name string
// ABI uint16
// Type uint8
// Flag uint8
// Flag2 uint8
// Siz uint32
// Align uint32
// }
type Sym [SymSize]byte
const SymSize = stringRefSize + 2 + 1 + 1 + 1 + 4 + 4
const SymABIstatic = ^uint16(0)
const (
ObjFlagShared = 1 << iota // this object is built with -shared
_ // was ObjFlagNeedNameExpansion
ObjFlagFromAssembly // object is from asm src, not go
ObjFlagUnlinkable // unlinkable package (linker will emit an error)
)
// Sym.Flag
const (
SymFlagDupok = 1 << iota
SymFlagLocal
SymFlagTypelink
SymFlagLeaf
SymFlagNoSplit
SymFlagReflectMethod
SymFlagGoType
)
// Sym.Flag2
const (
SymFlagUsedInIface = 1 << iota
SymFlagItab
SymFlagDict
SymFlagPkgInit
)
// Returns the length of the name of the symbol.
func (s *Sym) NameLen(r *Reader) int {
return int(binary.LittleEndian.Uint32(s[:]))
}
func (s *Sym) Name(r *Reader) string {
len := binary.LittleEndian.Uint32(s[:])
off := binary.LittleEndian.Uint32(s[4:])
return r.StringAt(off, len)
}
func (s *Sym) ABI() uint16 { return binary.LittleEndian.Uint16(s[8:]) }
func (s *Sym) Type() uint8 { return s[10] }
func (s *Sym) Flag() uint8 { return s[11] }
func (s *Sym) Flag2() uint8 { return s[12] }
func (s *Sym) Siz() uint32 { return binary.LittleEndian.Uint32(s[13:]) }
func (s *Sym) Align() uint32 { return binary.LittleEndian.Uint32(s[17:]) }
func (s *Sym) Dupok() bool { return s.Flag()&SymFlagDupok != 0 }
func (s *Sym) Local() bool { return s.Flag()&SymFlagLocal != 0 }
func (s *Sym) Typelink() bool { return s.Flag()&SymFlagTypelink != 0 }
func (s *Sym) Leaf() bool { return s.Flag()&SymFlagLeaf != 0 }
func (s *Sym) NoSplit() bool { return s.Flag()&SymFlagNoSplit != 0 }
func (s *Sym) ReflectMethod() bool { return s.Flag()&SymFlagReflectMethod != 0 }
func (s *Sym) IsGoType() bool { return s.Flag()&SymFlagGoType != 0 }
func (s *Sym) UsedInIface() bool { return s.Flag2()&SymFlagUsedInIface != 0 }
func (s *Sym) IsItab() bool { return s.Flag2()&SymFlagItab != 0 }
func (s *Sym) IsDict() bool { return s.Flag2()&SymFlagDict != 0 }
func (s *Sym) IsPkgInit() bool { return s.Flag2()&SymFlagPkgInit != 0 }
func (s *Sym) SetName(x string, w *Writer) {
binary.LittleEndian.PutUint32(s[:], uint32(len(x)))
binary.LittleEndian.PutUint32(s[4:], w.stringOff(x))
}
func (s *Sym) SetABI(x uint16) { binary.LittleEndian.PutUint16(s[8:], x) }
func (s *Sym) SetType(x uint8) { s[10] = x }
func (s *Sym) SetFlag(x uint8) { s[11] = x }
func (s *Sym) SetFlag2(x uint8) { s[12] = x }
func (s *Sym) SetSiz(x uint32) { binary.LittleEndian.PutUint32(s[13:], x) }
func (s *Sym) SetAlign(x uint32) { binary.LittleEndian.PutUint32(s[17:], x) }
func (s *Sym) Write(w *Writer) { w.Bytes(s[:]) }
// for testing
func (s *Sym) fromBytes(b []byte) { copy(s[:], b) }
// Symbol reference.
type SymRef struct {
PkgIdx uint32
SymIdx uint32
}
func (s SymRef) IsZero() bool { return s == SymRef{} }
// Hash64
type Hash64Type [Hash64Size]byte
const Hash64Size = 8
// Hash
type HashType [HashSize]byte
const HashSize = 16 // truncated SHA256
// Relocation.
//
// Serialized format:
//
// Reloc struct {
// Off int32
// Siz uint8
// Type uint16
// Add int64
// Sym SymRef
// }
type Reloc [RelocSize]byte
const RelocSize = 4 + 1 + 2 + 8 + 8
func (r *Reloc) Off() int32 { return int32(binary.LittleEndian.Uint32(r[:])) }
func (r *Reloc) Siz() uint8 { return r[4] }
func (r *Reloc) Type() uint16 { return binary.LittleEndian.Uint16(r[5:]) }
func (r *Reloc) Add() int64 { return int64(binary.LittleEndian.Uint64(r[7:])) }
func (r *Reloc) Sym() SymRef {
return SymRef{binary.LittleEndian.Uint32(r[15:]), binary.LittleEndian.Uint32(r[19:])}
}
func (r *Reloc) SetOff(x int32) { binary.LittleEndian.PutUint32(r[:], uint32(x)) }
func (r *Reloc) SetSiz(x uint8) { r[4] = x }
func (r *Reloc) SetType(x uint16) { binary.LittleEndian.PutUint16(r[5:], x) }
func (r *Reloc) SetAdd(x int64) { binary.LittleEndian.PutUint64(r[7:], uint64(x)) }
func (r *Reloc) SetSym(x SymRef) {
binary.LittleEndian.PutUint32(r[15:], x.PkgIdx)
binary.LittleEndian.PutUint32(r[19:], x.SymIdx)
}
func (r *Reloc) Set(off int32, size uint8, typ uint16, add int64, sym SymRef) {
r.SetOff(off)
r.SetSiz(size)
r.SetType(typ)
r.SetAdd(add)
r.SetSym(sym)
}
func (r *Reloc) Write(w *Writer) { w.Bytes(r[:]) }
// for testing
func (r *Reloc) fromBytes(b []byte) { copy(r[:], b) }
// Aux symbol info.
//
// Serialized format:
//
// Aux struct {
// Type uint8
// Sym SymRef
// }
type Aux [AuxSize]byte
const AuxSize = 1 + 8
// Aux Type
const (
AuxGotype = iota
AuxFuncInfo
AuxFuncdata
AuxDwarfInfo
AuxDwarfLoc
AuxDwarfRanges
AuxDwarfLines
AuxPcsp
AuxPcfile
AuxPcline
AuxPcinline
AuxPcdata
)
func (a *Aux) Type() uint8 { return a[0] }
func (a *Aux) Sym() SymRef {
return SymRef{binary.LittleEndian.Uint32(a[1:]), binary.LittleEndian.Uint32(a[5:])}
}
func (a *Aux) SetType(x uint8) { a[0] = x }
func (a *Aux) SetSym(x SymRef) {
binary.LittleEndian.PutUint32(a[1:], x.PkgIdx)
binary.LittleEndian.PutUint32(a[5:], x.SymIdx)
}
func (a *Aux) Write(w *Writer) { w.Bytes(a[:]) }
// for testing
func (a *Aux) fromBytes(b []byte) { copy(a[:], b) }
// Referenced symbol flags.
//
// Serialized format:
//
// RefFlags struct {
// Sym symRef
// Flag uint8
// Flag2 uint8
// }
type RefFlags [RefFlagsSize]byte
const RefFlagsSize = 8 + 1 + 1
func (r *RefFlags) Sym() SymRef {
return SymRef{binary.LittleEndian.Uint32(r[:]), binary.LittleEndian.Uint32(r[4:])}
}
func (r *RefFlags) Flag() uint8 { return r[8] }
func (r *RefFlags) Flag2() uint8 { return r[9] }
func (r *RefFlags) SetSym(x SymRef) {
binary.LittleEndian.PutUint32(r[:], x.PkgIdx)
binary.LittleEndian.PutUint32(r[4:], x.SymIdx)
}
func (r *RefFlags) SetFlag(x uint8) { r[8] = x }
func (r *RefFlags) SetFlag2(x uint8) { r[9] = x }
func (r *RefFlags) Write(w *Writer) { w.Bytes(r[:]) }
// Used to construct an artificially large array type when reading an
// item from the object file relocs section or aux sym section (needs
// to work on 32-bit as well as 64-bit). See issue 41621.
const huge = (1<<31 - 1) / RelocSize
// Referenced symbol name.
//
// Serialized format:
//
// RefName struct {
// Sym symRef
// Name string
// }
type RefName [RefNameSize]byte
const RefNameSize = 8 + stringRefSize
func (n *RefName) Sym() SymRef {
return SymRef{binary.LittleEndian.Uint32(n[:]), binary.LittleEndian.Uint32(n[4:])}
}
func (n *RefName) Name(r *Reader) string {
len := binary.LittleEndian.Uint32(n[8:])
off := binary.LittleEndian.Uint32(n[12:])
return r.StringAt(off, len)
}
func (n *RefName) SetSym(x SymRef) {
binary.LittleEndian.PutUint32(n[:], x.PkgIdx)
binary.LittleEndian.PutUint32(n[4:], x.SymIdx)
}
func (n *RefName) SetName(x string, w *Writer) {
binary.LittleEndian.PutUint32(n[8:], uint32(len(x)))
binary.LittleEndian.PutUint32(n[12:], w.stringOff(x))
}
func (n *RefName) Write(w *Writer) { w.Bytes(n[:]) }
type Writer struct {
wr *bio.Writer
stringMap map[string]uint32
off uint32 // running offset
b [8]byte // scratch space for writing bytes
}
func NewWriter(wr *bio.Writer) *Writer {
return &Writer{wr: wr, stringMap: make(map[string]uint32)}
}
func (w *Writer) AddString(s string) {
if _, ok := w.stringMap[s]; ok {
return
}
w.stringMap[s] = w.off
w.RawString(s)
}
func (w *Writer) stringOff(s string) uint32 {
off, ok := w.stringMap[s]
if !ok {
panic(fmt.Sprintf("writeStringRef: string not added: %q", s))
}
return off
}
func (w *Writer) StringRef(s string) {
w.Uint32(uint32(len(s)))
w.Uint32(w.stringOff(s))
}
func (w *Writer) RawString(s string) {
w.wr.WriteString(s)
w.off += uint32(len(s))
}
func (w *Writer) Bytes(s []byte) {
w.wr.Write(s)
w.off += uint32(len(s))
}
func (w *Writer) Uint64(x uint64) {
binary.LittleEndian.PutUint64(w.b[:], x)
w.wr.Write(w.b[:])
w.off += 8
}
func (w *Writer) Uint32(x uint32) {
binary.LittleEndian.PutUint32(w.b[:4], x)
w.wr.Write(w.b[:4])
w.off += 4
}
func (w *Writer) Uint16(x uint16) {
binary.LittleEndian.PutUint16(w.b[:2], x)
w.wr.Write(w.b[:2])
w.off += 2
}
func (w *Writer) Uint8(x uint8) {
w.wr.WriteByte(x)
w.off++
}
func (w *Writer) Offset() uint32 {
return w.off
}
type Reader struct {
b []byte // mmapped bytes, if not nil
readonly bool // whether b is backed with read-only memory
start uint32
h Header // keep block offsets
}
func NewReaderFromBytes(b []byte, readonly bool) *Reader {
r := &Reader{b: b, readonly: readonly, start: 0}
err := r.h.Read(r)
if err != nil {
return nil
}
return r
}
func (r *Reader) BytesAt(off uint32, len int) []byte {
if len == 0 {
return nil
}
end := int(off) + len
return r.b[int(off):end:end]
}
func (r *Reader) uint64At(off uint32) uint64 {
b := r.BytesAt(off, 8)
return binary.LittleEndian.Uint64(b)
}
func (r *Reader) int64At(off uint32) int64 {
return int64(r.uint64At(off))
}
func (r *Reader) uint32At(off uint32) uint32 {
b := r.BytesAt(off, 4)
return binary.LittleEndian.Uint32(b)
}
func (r *Reader) int32At(off uint32) int32 {
return int32(r.uint32At(off))
}
func (r *Reader) uint16At(off uint32) uint16 {
b := r.BytesAt(off, 2)
return binary.LittleEndian.Uint16(b)
}
func (r *Reader) uint8At(off uint32) uint8 {
b := r.BytesAt(off, 1)
return b[0]
}
func (r *Reader) StringAt(off uint32, len uint32) string {
b := r.b[off : off+len]
if r.readonly {
return toString(b) // backed by RO memory, ok to make unsafe string
}
return string(b)
}
func toString(b []byte) string {
if len(b) == 0 {
return ""
}
var s string
hdr := (*unsafeheader.String)(unsafe.Pointer(&s))
hdr.Data = unsafe.Pointer(&b[0])
hdr.Len = len(b)
return s
}
func (r *Reader) StringRef(off uint32) string {
l := r.uint32At(off)
return r.StringAt(r.uint32At(off+4), l)
}
func (r *Reader) Fingerprint() FingerprintType {
return r.h.Fingerprint
}
func (r *Reader) Autolib() []ImportedPkg {
n := (r.h.Offsets[BlkAutolib+1] - r.h.Offsets[BlkAutolib]) / importedPkgSize
s := make([]ImportedPkg, n)
off := r.h.Offsets[BlkAutolib]
for i := range s {
s[i].Pkg = r.StringRef(off)
copy(s[i].Fingerprint[:], r.BytesAt(off+stringRefSize, len(s[i].Fingerprint)))
off += importedPkgSize
}
return s
}
func (r *Reader) Pkglist() []string {
n := (r.h.Offsets[BlkPkgIdx+1] - r.h.Offsets[BlkPkgIdx]) / stringRefSize
s := make([]string, n)
off := r.h.Offsets[BlkPkgIdx]
for i := range s {
s[i] = r.StringRef(off)
off += stringRefSize
}
return s
}
func (r *Reader) NPkg() int {
return int(r.h.Offsets[BlkPkgIdx+1]-r.h.Offsets[BlkPkgIdx]) / stringRefSize
}
func (r *Reader) Pkg(i int) string {
off := r.h.Offsets[BlkPkgIdx] + uint32(i)*stringRefSize
return r.StringRef(off)
}
func (r *Reader) NFile() int {
return int(r.h.Offsets[BlkFile+1]-r.h.Offsets[BlkFile]) / stringRefSize
}
func (r *Reader) File(i int) string {
off := r.h.Offsets[BlkFile] + uint32(i)*stringRefSize
return r.StringRef(off)
}
func (r *Reader) NSym() int {
return int(r.h.Offsets[BlkSymdef+1]-r.h.Offsets[BlkSymdef]) / SymSize
}
func (r *Reader) NHashed64def() int {
return int(r.h.Offsets[BlkHashed64def+1]-r.h.Offsets[BlkHashed64def]) / SymSize
}
func (r *Reader) NHasheddef() int {
return int(r.h.Offsets[BlkHasheddef+1]-r.h.Offsets[BlkHasheddef]) / SymSize
}
func (r *Reader) NNonpkgdef() int {
return int(r.h.Offsets[BlkNonpkgdef+1]-r.h.Offsets[BlkNonpkgdef]) / SymSize
}
func (r *Reader) NNonpkgref() int {
return int(r.h.Offsets[BlkNonpkgref+1]-r.h.Offsets[BlkNonpkgref]) / SymSize
}
// SymOff returns the offset of the i-th symbol.
func (r *Reader) SymOff(i uint32) uint32 {
return r.h.Offsets[BlkSymdef] + uint32(i*SymSize)
}
// Sym returns a pointer to the i-th symbol.
func (r *Reader) Sym(i uint32) *Sym {
off := r.SymOff(i)
return (*Sym)(unsafe.Pointer(&r.b[off]))
}
// NRefFlags returns the number of referenced symbol flags.
func (r *Reader) NRefFlags() int {
return int(r.h.Offsets[BlkRefFlags+1]-r.h.Offsets[BlkRefFlags]) / RefFlagsSize
}
// RefFlags returns a pointer to the i-th referenced symbol flags.
// Note: here i is not a local symbol index, just a counter.
func (r *Reader) RefFlags(i int) *RefFlags {
off := r.h.Offsets[BlkRefFlags] + uint32(i*RefFlagsSize)
return (*RefFlags)(unsafe.Pointer(&r.b[off]))
}
// Hash64 returns the i-th short hashed symbol's hash.
// Note: here i is the index of short hashed symbols, not all symbols
// (unlike other accessors).
func (r *Reader) Hash64(i uint32) uint64 {
off := r.h.Offsets[BlkHash64] + uint32(i*Hash64Size)
return r.uint64At(off)
}
// Hash returns a pointer to the i-th hashed symbol's hash.
// Note: here i is the index of hashed symbols, not all symbols
// (unlike other accessors).
func (r *Reader) Hash(i uint32) *HashType {
off := r.h.Offsets[BlkHash] + uint32(i*HashSize)
return (*HashType)(unsafe.Pointer(&r.b[off]))
}
// NReloc returns the number of relocations of the i-th symbol.
func (r *Reader) NReloc(i uint32) int {
relocIdxOff := r.h.Offsets[BlkRelocIdx] + uint32(i*4)
return int(r.uint32At(relocIdxOff+4) - r.uint32At(relocIdxOff))
}
// RelocOff returns the offset of the j-th relocation of the i-th symbol.
func (r *Reader) RelocOff(i uint32, j int) uint32 {
relocIdxOff := r.h.Offsets[BlkRelocIdx] + uint32(i*4)
relocIdx := r.uint32At(relocIdxOff)
return r.h.Offsets[BlkReloc] + (relocIdx+uint32(j))*uint32(RelocSize)
}
// Reloc returns a pointer to the j-th relocation of the i-th symbol.
func (r *Reader) Reloc(i uint32, j int) *Reloc {
off := r.RelocOff(i, j)
return (*Reloc)(unsafe.Pointer(&r.b[off]))
}
// Relocs returns a pointer to the relocations of the i-th symbol.
func (r *Reader) Relocs(i uint32) []Reloc {
off := r.RelocOff(i, 0)
n := r.NReloc(i)
return (*[huge]Reloc)(unsafe.Pointer(&r.b[off]))[:n:n]
}
// NAux returns the number of aux symbols of the i-th symbol.
func (r *Reader) NAux(i uint32) int {
auxIdxOff := r.h.Offsets[BlkAuxIdx] + i*4
return int(r.uint32At(auxIdxOff+4) - r.uint32At(auxIdxOff))
}
// AuxOff returns the offset of the j-th aux symbol of the i-th symbol.
func (r *Reader) AuxOff(i uint32, j int) uint32 {
auxIdxOff := r.h.Offsets[BlkAuxIdx] + i*4
auxIdx := r.uint32At(auxIdxOff)
return r.h.Offsets[BlkAux] + (auxIdx+uint32(j))*uint32(AuxSize)
}
// Aux returns a pointer to the j-th aux symbol of the i-th symbol.
func (r *Reader) Aux(i uint32, j int) *Aux {
off := r.AuxOff(i, j)
return (*Aux)(unsafe.Pointer(&r.b[off]))
}
// Auxs returns the aux symbols of the i-th symbol.
func (r *Reader) Auxs(i uint32) []Aux {
off := r.AuxOff(i, 0)
n := r.NAux(i)
return (*[huge]Aux)(unsafe.Pointer(&r.b[off]))[:n:n]
}
// DataOff returns the offset of the i-th symbol's data.
func (r *Reader) DataOff(i uint32) uint32 {
dataIdxOff := r.h.Offsets[BlkDataIdx] + i*4
return r.h.Offsets[BlkData] + r.uint32At(dataIdxOff)
}
// DataSize returns the size of the i-th symbol's data.
func (r *Reader) DataSize(i uint32) int {
dataIdxOff := r.h.Offsets[BlkDataIdx] + i*4
return int(r.uint32At(dataIdxOff+4) - r.uint32At(dataIdxOff))
}
// Data returns the i-th symbol's data.
func (r *Reader) Data(i uint32) []byte {
dataIdxOff := r.h.Offsets[BlkDataIdx] + i*4
base := r.h.Offsets[BlkData]
off := r.uint32At(dataIdxOff)
end := r.uint32At(dataIdxOff + 4)
return r.BytesAt(base+off, int(end-off))
}
// NRefName returns the number of referenced symbol names.
func (r *Reader) NRefName() int {
return int(r.h.Offsets[BlkRefName+1]-r.h.Offsets[BlkRefName]) / RefNameSize
}
// RefName returns a pointer to the i-th referenced symbol name.
// Note: here i is not a local symbol index, just a counter.
func (r *Reader) RefName(i int) *RefName {
off := r.h.Offsets[BlkRefName] + uint32(i*RefNameSize)
return (*RefName)(unsafe.Pointer(&r.b[off]))
}
// ReadOnly returns whether r.BytesAt returns read-only bytes.
func (r *Reader) ReadOnly() bool {
return r.readonly
}
// Flags returns the flag bits read from the object file header.
func (r *Reader) Flags() uint32 {
return r.h.Flags
}
func (r *Reader) Shared() bool { return r.Flags()&ObjFlagShared != 0 }
func (r *Reader) FromAssembly() bool { return r.Flags()&ObjFlagFromAssembly != 0 }
func (r *Reader) Unlinkable() bool { return r.Flags()&ObjFlagUnlinkable != 0 }