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123 lines
2.8 KiB
Go
123 lines
2.8 KiB
Go
package line
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import (
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"bytes"
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"encoding/binary"
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"github.com/derekparker/delve/dwarf/util"
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)
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type DebugLinePrologue struct {
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UnitLength uint32
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Version uint16
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Length uint32
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MinInstrLength uint8
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InitialIsStmt uint8
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LineBase int8
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LineRange uint8
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OpcodeBase uint8
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StdOpLengths []uint8
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}
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type DebugLineInfo struct {
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Prologue *DebugLinePrologue
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IncludeDirs []string
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FileNames []*FileEntry
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Instructions []byte
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Lookup map[string]*FileEntry
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}
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type FileEntry struct {
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Name string
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DirIdx uint64
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LastModTime uint64
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Length uint64
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}
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type DebugLines []*DebugLineInfo
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func (d *DebugLines) GetLineInfo(name string) *DebugLineInfo {
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// Find in which table file exists and return it.
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for _, l := range *d {
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if _, ok := l.Lookup[name]; ok {
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return l
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}
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}
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return nil
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}
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func Parse(data []byte) DebugLines {
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var (
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lines = make(DebugLines, 0)
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buf = bytes.NewBuffer(data)
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)
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// We have to parse multiple file name tables here.
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for buf.Len() > 0 {
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dbl := new(DebugLineInfo)
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dbl.Lookup = make(map[string]*FileEntry)
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parseDebugLinePrologue(dbl, buf)
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parseIncludeDirs(dbl, buf)
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parseFileEntries(dbl, buf)
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// Instructions size calculation breakdown:
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// - dbl.Prologue.UnitLength is the length of the entire unit, not including the 4 bytes to represent that length.
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// - dbl.Prologue.Length is the length of the prologue not including unit length, version or prologue length itself.
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// - So you have UnitLength - PrologueLength - (version_length_bytes(2) + prologue_length_bytes(4)).
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dbl.Instructions = buf.Next(int(dbl.Prologue.UnitLength - dbl.Prologue.Length - 6))
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lines = append(lines, dbl)
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}
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return lines
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}
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func parseDebugLinePrologue(dbl *DebugLineInfo, buf *bytes.Buffer) {
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p := new(DebugLinePrologue)
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p.UnitLength = binary.LittleEndian.Uint32(buf.Next(4))
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p.Version = binary.LittleEndian.Uint16(buf.Next(2))
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p.Length = binary.LittleEndian.Uint32(buf.Next(4))
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p.MinInstrLength = uint8(buf.Next(1)[0])
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p.InitialIsStmt = uint8(buf.Next(1)[0])
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p.LineBase = int8(buf.Next(1)[0])
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p.LineRange = uint8(buf.Next(1)[0])
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p.OpcodeBase = uint8(buf.Next(1)[0])
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p.StdOpLengths = make([]uint8, p.OpcodeBase-1)
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binary.Read(buf, binary.LittleEndian, &p.StdOpLengths)
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dbl.Prologue = p
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}
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func parseIncludeDirs(info *DebugLineInfo, buf *bytes.Buffer) {
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for {
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str, _ := util.ParseString(buf)
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if str == "" {
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break
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}
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info.IncludeDirs = append(info.IncludeDirs, str)
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}
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}
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func parseFileEntries(info *DebugLineInfo, buf *bytes.Buffer) {
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for {
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entry := new(FileEntry)
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name, _ := util.ParseString(buf)
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if name == "" {
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break
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}
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entry.Name = name
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entry.DirIdx, _ = util.DecodeULEB128(buf)
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entry.LastModTime, _ = util.DecodeULEB128(buf)
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entry.Length, _ = util.DecodeULEB128(buf)
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info.FileNames = append(info.FileNames, entry)
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info.Lookup[name] = entry
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}
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}
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