go/src/cmd/internal/goobj2/objfile.go
Jeremy Faller 9bdaf99966 [dev.link] use per package filenames to build pclntab
In order to prevent renumbering of filenames in pclntab generation, use
the per-package file list (previously only used for DWARF generation) as
file-indices. This is the largest step to eliminate renumbering of
filenames in pclntab.

Note, this is probably not the final state of the file table within the
object file. In this form, the linker loads all filenames for all
objects. I'll move to storing the filenames as regular string
symbols,and defaulting all string symbols to using the larger hash value
to make generation of pcln simplest, and most memory friendly.

Change-Id: I23daafa3f4b4535076e23100200ae0e7163aafe0
Reviewed-on: https://go-review.googlesource.com/c/go/+/245485
Run-TryBot: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2020-08-10 16:55:06 +00:00

859 lines
22 KiB
Go

// 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.
// Go new object file format, reading and writing.
package goobj2 // TODO: replace the goobj package?
import (
"bytes"
"cmd/internal/bio"
"crypto/sha1"
"encoding/binary"
"errors"
"fmt"
"internal/unsafeheader"
"io"
"unsafe"
)
// New object file format.
//
// Header struct {
// Magic [...]byte // "\x00go116ld"
// 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 uint8
// Add int64
// Sym symRef
// }
//
// Aux [...]struct {
// Type uint8
// Sym symRef
// }
//
// Data [...]byte
// Pcdata [...]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 natually 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
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
BlkPcdata
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 = "\x00go116ld"
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
ObjFlagNeedNameExpansion // the linker needs to expand `"".` to package path in symbol names
ObjFlagFromAssembly // object is from asm src, not go
)
// Sym.Flag
const (
SymFlagDupok = 1 << iota
SymFlagLocal
SymFlagTypelink
SymFlagLeaf
SymFlagNoSplit
SymFlagReflectMethod
SymFlagGoType
SymFlagTopFrame
)
// Sym.Flag2
const (
SymFlagUsedInIface = 1 << iota
SymFlagItab
)
// 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) TopFrame() bool { return s.Flag()&SymFlagTopFrame != 0 }
func (s *Sym) UsedInIface() bool { return s.Flag2()&SymFlagUsedInIface != 0 }
func (s *Sym) IsItab() bool { return s.Flag2()&SymFlagItab != 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
}
// Hash64
type Hash64Type [Hash64Size]byte
const Hash64Size = 8
// Hash
type HashType [HashSize]byte
const HashSize = sha1.Size
// Relocation.
//
// Serialized format:
// Reloc struct {
// Off int32
// Siz uint8
// Type uint8
// Add int64
// Sym SymRef
// }
type Reloc [RelocSize]byte
const RelocSize = 4 + 1 + 1 + 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() uint8 { return r[5] }
func (r *Reloc) Add() int64 { return int64(binary.LittleEndian.Uint64(r[6:])) }
func (r *Reloc) Sym() SymRef {
return SymRef{binary.LittleEndian.Uint32(r[14:]), binary.LittleEndian.Uint32(r[18:])}
}
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 uint8) { r[5] = x }
func (r *Reloc) SetAdd(x int64) { binary.LittleEndian.PutUint64(r[6:], uint64(x)) }
func (r *Reloc) SetSym(x SymRef) {
binary.LittleEndian.PutUint32(r[14:], x.PkgIdx)
binary.LittleEndian.PutUint32(r[18:], x.SymIdx)
}
func (r *Reloc) Set(off int32, size uint8, typ uint8, 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
// TODO: more. Pcdata?
)
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[:]) }
// 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
}
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) {
var b [8]byte
binary.LittleEndian.PutUint64(b[:], x)
w.wr.Write(b[:])
w.off += 8
}
func (w *Writer) Uint32(x uint32) {
var b [4]byte
binary.LittleEndian.PutUint32(b[:], x)
w.wr.Write(b[:])
w.off += 4
}
func (w *Writer) Uint16(x uint16) {
var b [2]byte
binary.LittleEndian.PutUint16(b[:], x)
w.wr.Write(b[:])
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
rd io.ReaderAt
start uint32
h Header // keep block offsets
}
func NewReaderFromBytes(b []byte, readonly bool) *Reader {
r := &Reader{b: b, readonly: readonly, rd: bytes.NewReader(b), 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 (*[1 << 20]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 (*[1 << 20]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))
}
// AuxDataBase returns the base offset of the aux data block.
func (r *Reader) PcdataBase() uint32 {
return r.h.Offsets[BlkPcdata]
}
// 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) NeedNameExpansion() bool { return r.Flags()&ObjFlagNeedNameExpansion != 0 }
func (r *Reader) FromAssembly() bool { return r.Flags()&ObjFlagFromAssembly != 0 }