// Copyright 2009 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.

// Package dwarf provides access to DWARF debugging information loaded from // executable files, as defined in the DWARF 2.0 Standard at // http://dwarfstd.org/doc/dwarf-2.0.0.pdf
package dwarf import ( ) // Data represents the DWARF debugging information // loaded from an executable file (for example, an ELF or Mach-O executable). type Data struct { // raw data abbrev []byte aranges []byte frame []byte info []byte line []byte pubnames []byte ranges []byte str []byte // New sections added in DWARF 5. addr []byte lineStr []byte strOffsets []byte rngLists []byte // parsed data abbrevCache map[uint64]abbrevTable bigEndian bool order binary.ByteOrder typeCache map[Offset]Type typeSigs map[uint64]*typeUnit unit []unit } var errSegmentSelector = errors.New("non-zero segment_selector size not supported") // New returns a new Data object initialized from the given parameters. // Rather than calling this function directly, clients should typically use // the DWARF method of the File type of the appropriate package debug/elf, // debug/macho, or debug/pe. // // The []byte arguments are the data from the corresponding debug section // in the object file; for example, for an ELF object, abbrev is the contents of // the ".debug_abbrev" section. func (, , , , , , , []byte) (*Data, error) { := &Data{ abbrev: , aranges: , frame: , info: , line: , pubnames: , ranges: , str: , abbrevCache: make(map[uint64]abbrevTable), typeCache: make(map[Offset]Type), typeSigs: make(map[uint64]*typeUnit), } // Sniff .debug_info to figure out byte order. // 32-bit DWARF: 4 byte length, 2 byte version. // 64-bit DWARf: 4 bytes of 0xff, 8 byte length, 2 byte version. if len(.info) < 6 { return nil, DecodeError{"info", Offset(len(.info)), "too short"} } := 4 if .info[0] == 0xff && .info[1] == 0xff && .info[2] == 0xff && .info[3] == 0xff { if len(.info) < 14 { return nil, DecodeError{"info", Offset(len(.info)), "too short"} } = 12 } // Fetch the version, a tiny 16-bit number (1, 2, 3, 4, 5). , := .info[], .info[+1] switch { case == 0 && == 0: return nil, DecodeError{"info", 4, "unsupported version 0"} case == 0: .bigEndian = true .order = binary.BigEndian case == 0: .bigEndian = false .order = binary.LittleEndian default: return nil, DecodeError{"info", 4, "cannot determine byte order"} } , := .parseUnits() if != nil { return nil, } .unit = return , nil } // AddTypes will add one .debug_types section to the DWARF data. A // typical object with DWARF version 4 debug info will have multiple // .debug_types sections. The name is used for error reporting only, // and serves to distinguish one .debug_types section from another. func ( *Data) ( string, []byte) error { return .parseTypes(, ) } // AddSection adds another DWARF section by name. The name should be a // DWARF section name such as ".debug_addr", ".debug_str_offsets", and // so forth. This approach is used for new DWARF sections added in // DWARF 5 and later. func ( *Data) ( string, []byte) error { var error switch { case ".debug_addr": .addr = case ".debug_line_str": .lineStr = case ".debug_str_offsets": .strOffsets = case ".debug_rnglists": .rngLists = } // Just ignore names that we don't yet support. return }