872 lines
		
	
	
		
			23 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			872 lines
		
	
	
		
			23 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
| // Copyright 2019 The Go Authors. All rights reserved.
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| // Use of this source code is governed by a BSD-style
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| // license that can be found in the LICENSE file.
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| 
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| // This package defines the Go object file format, and provide "low-level" functions
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| // for reading and writing object files.
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| 
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| // The object file is understood by the compiler, assembler, linker, and tools. They
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| // have "high level" code that operates on object files, handling application-specific
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| // logics, and use this package for the actual reading and writing. Specifically, the
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| // code below:
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| //
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| // - cmd/internal/obj/objfile.go (used by cmd/asm and cmd/compile)
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| // - cmd/internal/objfile/goobj.go (used cmd/nm, cmd/objdump)
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| // - cmd/link/internal/loader package (used by cmd/link)
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| //
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| // If the object file format changes, they may (or may not) need to change.
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| 
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| package goobj
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| 
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| import (
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| 	"bytes"
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| 	"github.com/twitchyliquid64/golang-asm/bio"
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| 	"crypto/sha1"
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| 	"encoding/binary"
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| 	"errors"
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| 	"fmt"
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| 	"github.com/twitchyliquid64/golang-asm/unsafeheader"
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| 	"io"
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| 	"unsafe"
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| )
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| 
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| // New object file format.
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| //
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| //    Header struct {
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| //       Magic       [...]byte   // "\x00go116ld"
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| //       Fingerprint [8]byte
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| //       Flags       uint32
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| //       Offsets     [...]uint32 // byte offset of each block below
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| //    }
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| //
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| //    Strings [...]struct {
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| //       Data [...]byte
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| //    }
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| //
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| //    Autolib  [...]struct { // imported packages (for file loading)
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| //       Pkg         string
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| //       Fingerprint [8]byte
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| //    }
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| //
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| //    PkgIndex [...]string // referenced packages by index
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| //
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| //    Files [...]string
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| //
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| //    SymbolDefs [...]struct {
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| //       Name  string
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| //       ABI   uint16
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| //       Type  uint8
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| //       Flag  uint8
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| //       Flag2 uint8
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| //       Size  uint32
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| //    }
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| //    Hashed64Defs [...]struct { // short hashed (content-addressable) symbol definitions
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| //       ... // same as SymbolDefs
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| //    }
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| //    HashedDefs [...]struct { // hashed (content-addressable) symbol definitions
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| //       ... // same as SymbolDefs
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| //    }
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| //    NonPkgDefs [...]struct { // non-pkg symbol definitions
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| //       ... // same as SymbolDefs
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| //    }
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| //    NonPkgRefs [...]struct { // non-pkg symbol references
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| //       ... // same as SymbolDefs
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| //    }
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| //
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| //    RefFlags [...]struct { // referenced symbol flags
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| //       Sym   symRef
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| //       Flag  uint8
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| //       Flag2 uint8
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| //    }
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| //
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| //    Hash64 [...][8]byte
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| //    Hash   [...][N]byte
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| //
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| //    RelocIndex [...]uint32 // index to Relocs
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| //    AuxIndex   [...]uint32 // index to Aux
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| //    DataIndex  [...]uint32 // offset to Data
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| //
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| //    Relocs [...]struct {
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| //       Off  int32
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| //       Size uint8
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| //       Type uint8
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| //       Add  int64
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| //       Sym  symRef
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| //    }
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| //
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| //    Aux [...]struct {
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| //       Type uint8
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| //       Sym  symRef
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| //    }
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| //
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| //    Data   [...]byte
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| //    Pcdata [...]byte
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| //
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| //    // blocks only used by tools (objdump, nm)
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| //
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| //    RefNames [...]struct { // referenced symbol names
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| //       Sym  symRef
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| //       Name string
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| //       // TODO: include ABI version as well?
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| //    }
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| //
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| // string is encoded as is a uint32 length followed by a uint32 offset
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| // that points to the corresponding string bytes.
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| //
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| // symRef is struct { PkgIdx, SymIdx uint32 }.
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| //
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| // Slice type (e.g. []symRef) is encoded as a length prefix (uint32)
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| // followed by that number of elements.
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| //
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| // The types below correspond to the encoded data structure in the
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| // object file.
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| 
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| // Symbol indexing.
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| //
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| // Each symbol is referenced with a pair of indices, { PkgIdx, SymIdx },
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| // as the symRef struct above.
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| //
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| // PkgIdx is either a predeclared index (see PkgIdxNone below) or
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| // an index of an imported package. For the latter case, PkgIdx is the
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| // index of the package in the PkgIndex array. 0 is an invalid index.
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| //
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| // SymIdx is the index of the symbol in the given package.
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| // - If PkgIdx is PkgIdxSelf, SymIdx is the index of the symbol in the
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| //   SymbolDefs array.
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| // - If PkgIdx is PkgIdxHashed64, SymIdx is the index of the symbol in the
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| //   Hashed64Defs array.
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| // - If PkgIdx is PkgIdxHashed, SymIdx is the index of the symbol in the
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| //   HashedDefs array.
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| // - If PkgIdx is PkgIdxNone, SymIdx is the index of the symbol in the
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| //   NonPkgDefs array (could natually overflow to NonPkgRefs array).
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| // - Otherwise, SymIdx is the index of the symbol in some other package's
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| //   SymbolDefs array.
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| //
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| // {0, 0} represents a nil symbol. Otherwise PkgIdx should not be 0.
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| //
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| // Hash contains the content hashes of content-addressable symbols, of
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| // which PkgIdx is PkgIdxHashed, in the same order of HashedDefs array.
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| // Hash64 is similar, for PkgIdxHashed64 symbols.
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| //
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| // RelocIndex, AuxIndex, and DataIndex contains indices/offsets to
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| // Relocs/Aux/Data blocks, one element per symbol, first for all the
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| // defined symbols, then all the defined hashed and non-package symbols,
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| // in the same order of SymbolDefs/Hashed64Defs/HashedDefs/NonPkgDefs
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| // arrays. For N total defined symbols, the array is of length N+1. The
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| // last element is the total number of relocations (aux symbols, data
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| // blocks, etc.).
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| //
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| // They can be accessed by index. For the i-th symbol, its relocations
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| // are the RelocIndex[i]-th (inclusive) to RelocIndex[i+1]-th (exclusive)
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| // elements in the Relocs array. Aux/Data are likewise. (The index is
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| // 0-based.)
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| 
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| // Auxiliary symbols.
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| //
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| // Each symbol may (or may not) be associated with a number of auxiliary
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| // symbols. They are described in the Aux block. See Aux struct below.
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| // Currently a symbol's Gotype, FuncInfo, and associated DWARF symbols
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| // are auxiliary symbols.
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| 
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| const stringRefSize = 8 // two uint32s
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| 
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| type FingerprintType [8]byte
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| 
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| func (fp FingerprintType) IsZero() bool { return fp == FingerprintType{} }
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| 
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| // Package Index.
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| const (
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| 	PkgIdxNone     = (1<<31 - 1) - iota // Non-package symbols
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| 	PkgIdxHashed64                      // Short hashed (content-addressable) symbols
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| 	PkgIdxHashed                        // Hashed (content-addressable) symbols
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| 	PkgIdxBuiltin                       // Predefined runtime symbols (ex: runtime.newobject)
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| 	PkgIdxSelf                          // Symbols defined in the current package
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| 	PkgIdxInvalid  = 0
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| 	// The index of other referenced packages starts from 1.
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| )
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| 
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| // Blocks
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| const (
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| 	BlkAutolib = iota
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| 	BlkPkgIdx
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| 	BlkFile
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| 	BlkSymdef
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| 	BlkHashed64def
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| 	BlkHasheddef
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| 	BlkNonpkgdef
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| 	BlkNonpkgref
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| 	BlkRefFlags
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| 	BlkHash64
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| 	BlkHash
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| 	BlkRelocIdx
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| 	BlkAuxIdx
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| 	BlkDataIdx
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| 	BlkReloc
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| 	BlkAux
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| 	BlkData
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| 	BlkPcdata
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| 	BlkRefName
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| 	BlkEnd
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| 	NBlk
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| )
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| 
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| // File header.
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| // TODO: probably no need to export this.
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| type Header struct {
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| 	Magic       string
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| 	Fingerprint FingerprintType
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| 	Flags       uint32
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| 	Offsets     [NBlk]uint32
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| }
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| 
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| const Magic = "\x00go116ld"
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| 
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| func (h *Header) Write(w *Writer) {
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| 	w.RawString(h.Magic)
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| 	w.Bytes(h.Fingerprint[:])
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| 	w.Uint32(h.Flags)
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| 	for _, x := range h.Offsets {
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| 		w.Uint32(x)
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| 	}
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| }
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| 
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| func (h *Header) Read(r *Reader) error {
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| 	b := r.BytesAt(0, len(Magic))
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| 	h.Magic = string(b)
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| 	if h.Magic != Magic {
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| 		return errors.New("wrong magic, not a Go object file")
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| 	}
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| 	off := uint32(len(h.Magic))
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| 	copy(h.Fingerprint[:], r.BytesAt(off, len(h.Fingerprint)))
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| 	off += 8
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| 	h.Flags = r.uint32At(off)
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| 	off += 4
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| 	for i := range h.Offsets {
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| 		h.Offsets[i] = r.uint32At(off)
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| 		off += 4
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| 	}
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| 	return nil
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| }
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| 
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| func (h *Header) Size() int {
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| 	return len(h.Magic) + 4 + 4*len(h.Offsets)
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| }
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| 
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| // Autolib
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| type ImportedPkg struct {
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| 	Pkg         string
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| 	Fingerprint FingerprintType
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| }
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| 
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| const importedPkgSize = stringRefSize + 8
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| 
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| func (p *ImportedPkg) Write(w *Writer) {
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| 	w.StringRef(p.Pkg)
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| 	w.Bytes(p.Fingerprint[:])
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| }
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| 
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| // Symbol definition.
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| //
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| // Serialized format:
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| // Sym struct {
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| //    Name  string
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| //    ABI   uint16
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| //    Type  uint8
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| //    Flag  uint8
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| //    Flag2 uint8
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| //    Siz   uint32
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| //    Align uint32
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| // }
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| type Sym [SymSize]byte
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| 
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| const SymSize = stringRefSize + 2 + 1 + 1 + 1 + 4 + 4
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| 
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| const SymABIstatic = ^uint16(0)
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| 
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| const (
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| 	ObjFlagShared            = 1 << iota // this object is built with -shared
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| 	ObjFlagNeedNameExpansion             // the linker needs to expand `"".` to package path in symbol names
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| 	ObjFlagFromAssembly                  // object is from asm src, not go
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| )
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| 
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| // Sym.Flag
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| const (
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| 	SymFlagDupok = 1 << iota
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| 	SymFlagLocal
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| 	SymFlagTypelink
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| 	SymFlagLeaf
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| 	SymFlagNoSplit
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| 	SymFlagReflectMethod
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| 	SymFlagGoType
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| 	SymFlagTopFrame
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| )
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| 
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| // Sym.Flag2
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| const (
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| 	SymFlagUsedInIface = 1 << iota
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| 	SymFlagItab
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| )
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| 
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| // Returns the length of the name of the symbol.
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| func (s *Sym) NameLen(r *Reader) int {
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| 	return int(binary.LittleEndian.Uint32(s[:]))
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| }
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| 
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| func (s *Sym) Name(r *Reader) string {
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| 	len := binary.LittleEndian.Uint32(s[:])
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| 	off := binary.LittleEndian.Uint32(s[4:])
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| 	return r.StringAt(off, len)
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| }
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| 
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| func (s *Sym) ABI() uint16   { return binary.LittleEndian.Uint16(s[8:]) }
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| func (s *Sym) Type() uint8   { return s[10] }
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| func (s *Sym) Flag() uint8   { return s[11] }
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| func (s *Sym) Flag2() uint8  { return s[12] }
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| func (s *Sym) Siz() uint32   { return binary.LittleEndian.Uint32(s[13:]) }
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| func (s *Sym) Align() uint32 { return binary.LittleEndian.Uint32(s[17:]) }
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| 
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| func (s *Sym) Dupok() bool         { return s.Flag()&SymFlagDupok != 0 }
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| func (s *Sym) Local() bool         { return s.Flag()&SymFlagLocal != 0 }
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| func (s *Sym) Typelink() bool      { return s.Flag()&SymFlagTypelink != 0 }
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| func (s *Sym) Leaf() bool          { return s.Flag()&SymFlagLeaf != 0 }
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| func (s *Sym) NoSplit() bool       { return s.Flag()&SymFlagNoSplit != 0 }
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| func (s *Sym) ReflectMethod() bool { return s.Flag()&SymFlagReflectMethod != 0 }
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| func (s *Sym) IsGoType() bool      { return s.Flag()&SymFlagGoType != 0 }
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| func (s *Sym) TopFrame() bool      { return s.Flag()&SymFlagTopFrame != 0 }
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| func (s *Sym) UsedInIface() bool   { return s.Flag2()&SymFlagUsedInIface != 0 }
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| func (s *Sym) IsItab() bool        { return s.Flag2()&SymFlagItab != 0 }
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| 
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| func (s *Sym) SetName(x string, w *Writer) {
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| 	binary.LittleEndian.PutUint32(s[:], uint32(len(x)))
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| 	binary.LittleEndian.PutUint32(s[4:], w.stringOff(x))
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| }
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| 
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| func (s *Sym) SetABI(x uint16)   { binary.LittleEndian.PutUint16(s[8:], x) }
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| func (s *Sym) SetType(x uint8)   { s[10] = x }
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| func (s *Sym) SetFlag(x uint8)   { s[11] = x }
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| func (s *Sym) SetFlag2(x uint8)  { s[12] = x }
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| func (s *Sym) SetSiz(x uint32)   { binary.LittleEndian.PutUint32(s[13:], x) }
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| func (s *Sym) SetAlign(x uint32) { binary.LittleEndian.PutUint32(s[17:], x) }
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| 
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| func (s *Sym) Write(w *Writer) { w.Bytes(s[:]) }
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| 
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| // for testing
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| func (s *Sym) fromBytes(b []byte) { copy(s[:], b) }
 | |
| 
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| // Symbol reference.
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| type SymRef struct {
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| 	PkgIdx uint32
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| 	SymIdx uint32
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| }
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| 
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| // Hash64
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| type Hash64Type [Hash64Size]byte
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| 
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| const Hash64Size = 8
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| 
 | |
| // Hash
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| type HashType [HashSize]byte
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| 
 | |
| const HashSize = sha1.Size
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| 
 | |
| // Relocation.
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| //
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| // Serialized format:
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| // Reloc struct {
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| //    Off  int32
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| //    Siz  uint8
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| //    Type uint8
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| //    Add  int64
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| //    Sym  SymRef
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| // }
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| type Reloc [RelocSize]byte
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| 
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| const RelocSize = 4 + 1 + 1 + 8 + 8
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| 
 | |
| func (r *Reloc) Off() int32  { return int32(binary.LittleEndian.Uint32(r[:])) }
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| func (r *Reloc) Siz() uint8  { return r[4] }
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| func (r *Reloc) Type() uint8 { return r[5] }
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| func (r *Reloc) Add() int64  { return int64(binary.LittleEndian.Uint64(r[6:])) }
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| func (r *Reloc) Sym() SymRef {
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| 	return SymRef{binary.LittleEndian.Uint32(r[14:]), binary.LittleEndian.Uint32(r[18:])}
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| }
 | |
| 
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| func (r *Reloc) SetOff(x int32)  { binary.LittleEndian.PutUint32(r[:], uint32(x)) }
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| func (r *Reloc) SetSiz(x uint8)  { r[4] = x }
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| func (r *Reloc) SetType(x uint8) { r[5] = x }
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| func (r *Reloc) SetAdd(x int64)  { binary.LittleEndian.PutUint64(r[6:], uint64(x)) }
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| func (r *Reloc) SetSym(x SymRef) {
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| 	binary.LittleEndian.PutUint32(r[14:], x.PkgIdx)
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| 	binary.LittleEndian.PutUint32(r[18:], x.SymIdx)
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| }
 | |
| 
 | |
| func (r *Reloc) Set(off int32, size uint8, typ uint8, add int64, sym SymRef) {
 | |
| 	r.SetOff(off)
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| 	r.SetSiz(size)
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| 	r.SetType(typ)
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| 	r.SetAdd(add)
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| 	r.SetSym(sym)
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| }
 | |
| 
 | |
| 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 }
 |