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Diffstat (limited to 'src/cmd/internal/goobj/objfile.go')
| -rw-r--r-- | src/cmd/internal/goobj/objfile.go | 874 |
1 files changed, 874 insertions, 0 deletions
diff --git a/src/cmd/internal/goobj/objfile.go b/src/cmd/internal/goobj/objfile.go new file mode 100644 index 0000000..e6447e4 --- /dev/null +++ b/src/cmd/internal/goobj/objfile.go @@ -0,0 +1,874 @@ +// 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 ( + "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 + 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 artifically 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 +} + +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 (*[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) NeedNameExpansion() bool { return r.Flags()&ObjFlagNeedNameExpansion != 0 } +func (r *Reader) FromAssembly() bool { return r.Flags()&ObjFlagFromAssembly != 0 } |