849 lines
23 KiB
Go
849 lines
23 KiB
Go
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// Copyright 2015 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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package dwarf
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import (
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"errors"
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"fmt"
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"io"
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"path"
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"strings"
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)
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// A LineReader reads a sequence of LineEntry structures from a DWARF
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// "line" section for a single compilation unit. LineEntries occur in
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// order of increasing PC and each LineEntry gives metadata for the
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// instructions from that LineEntry's PC to just before the next
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// LineEntry's PC. The last entry will have its EndSequence field set.
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type LineReader struct {
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buf buf
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// Original .debug_line section data. Used by Seek.
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section []byte
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str []byte // .debug_str
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lineStr []byte // .debug_line_str
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// Header information
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version uint16
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addrsize int
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segmentSelectorSize int
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minInstructionLength int
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maxOpsPerInstruction int
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defaultIsStmt bool
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lineBase int
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lineRange int
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opcodeBase int
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opcodeLengths []int
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directories []string
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fileEntries []*LineFile
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programOffset Offset // section offset of line number program
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endOffset Offset // section offset of byte following program
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initialFileEntries int // initial length of fileEntries
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// Current line number program state machine registers
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state LineEntry // public state
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fileIndex int // private state
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}
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// A LineEntry is a row in a DWARF line table.
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type LineEntry struct {
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// Address is the program-counter value of a machine
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// instruction generated by the compiler. This LineEntry
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// applies to each instruction from Address to just before the
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// Address of the next LineEntry.
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Address uint64
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// OpIndex is the index of an operation within a VLIW
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// instruction. The index of the first operation is 0. For
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// non-VLIW architectures, it will always be 0. Address and
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// OpIndex together form an operation pointer that can
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// reference any individual operation within the instruction
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// stream.
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OpIndex int
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// File is the source file corresponding to these
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// instructions.
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File *LineFile
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// Line is the source code line number corresponding to these
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// instructions. Lines are numbered beginning at 1. It may be
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// 0 if these instructions cannot be attributed to any source
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// line.
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Line int
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// Column is the column number within the source line of these
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// instructions. Columns are numbered beginning at 1. It may
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// be 0 to indicate the "left edge" of the line.
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Column int
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// IsStmt indicates that Address is a recommended breakpoint
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// location, such as the beginning of a line, statement, or a
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// distinct subpart of a statement.
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IsStmt bool
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// BasicBlock indicates that Address is the beginning of a
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// basic block.
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BasicBlock bool
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// PrologueEnd indicates that Address is one (of possibly
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// many) PCs where execution should be suspended for a
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// breakpoint on entry to the containing function.
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//
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// Added in DWARF 3.
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PrologueEnd bool
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// EpilogueBegin indicates that Address is one (of possibly
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// many) PCs where execution should be suspended for a
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// breakpoint on exit from this function.
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//
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// Added in DWARF 3.
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EpilogueBegin bool
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// ISA is the instruction set architecture for these
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// instructions. Possible ISA values should be defined by the
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// applicable ABI specification.
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//
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// Added in DWARF 3.
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ISA int
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// Discriminator is an arbitrary integer indicating the block
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// to which these instructions belong. It serves to
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// distinguish among multiple blocks that may all have with
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// the same source file, line, and column. Where only one
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// block exists for a given source position, it should be 0.
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//
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// Added in DWARF 3.
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Discriminator int
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// EndSequence indicates that Address is the first byte after
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// the end of a sequence of target machine instructions. If it
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// is set, only this and the Address field are meaningful. A
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// line number table may contain information for multiple
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// potentially disjoint instruction sequences. The last entry
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// in a line table should always have EndSequence set.
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EndSequence bool
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}
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// A LineFile is a source file referenced by a DWARF line table entry.
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type LineFile struct {
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Name string
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Mtime uint64 // Implementation defined modification time, or 0 if unknown
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Length int // File length, or 0 if unknown
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}
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// LineReader returns a new reader for the line table of compilation
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// unit cu, which must be an Entry with tag TagCompileUnit.
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//
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// If this compilation unit has no line table, it returns nil, nil.
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func (d *Data) LineReader(cu *Entry) (*LineReader, error) {
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if d.line == nil {
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// No line tables available.
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return nil, nil
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}
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// Get line table information from cu.
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off, ok := cu.Val(AttrStmtList).(int64)
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if !ok {
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// cu has no line table.
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return nil, nil
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}
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if off > int64(len(d.line)) {
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return nil, errors.New("AttrStmtList value out of range")
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}
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// AttrCompDir is optional if all file names are absolute. Use
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// the empty string if it's not present.
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compDir, _ := cu.Val(AttrCompDir).(string)
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// Create the LineReader.
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u := &d.unit[d.offsetToUnit(cu.Offset)]
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buf := makeBuf(d, u, "line", Offset(off), d.line[off:])
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// The compilation directory is implicitly directories[0].
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r := LineReader{
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buf: buf,
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section: d.line,
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str: d.str,
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lineStr: d.lineStr,
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}
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// Read the header.
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if err := r.readHeader(compDir); err != nil {
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return nil, err
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}
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// Initialize line reader state.
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r.Reset()
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return &r, nil
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}
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// readHeader reads the line number program header from r.buf and sets
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// all of the header fields in r.
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func (r *LineReader) readHeader(compDir string) error {
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buf := &r.buf
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// Read basic header fields [DWARF2 6.2.4].
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hdrOffset := buf.off
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unitLength, dwarf64 := buf.unitLength()
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r.endOffset = buf.off + unitLength
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if r.endOffset > buf.off+Offset(len(buf.data)) {
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return DecodeError{"line", hdrOffset, fmt.Sprintf("line table end %d exceeds section size %d", r.endOffset, buf.off+Offset(len(buf.data)))}
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}
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r.version = buf.uint16()
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if buf.err == nil && (r.version < 2 || r.version > 5) {
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// DWARF goes to all this effort to make new opcodes
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// backward-compatible, and then adds fields right in
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// the middle of the header in new versions, so we're
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// picky about only supporting known line table
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// versions.
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return DecodeError{"line", hdrOffset, fmt.Sprintf("unknown line table version %d", r.version)}
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}
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if r.version >= 5 {
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r.addrsize = int(buf.uint8())
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r.segmentSelectorSize = int(buf.uint8())
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} else {
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r.addrsize = buf.format.addrsize()
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r.segmentSelectorSize = 0
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}
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var headerLength Offset
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if dwarf64 {
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headerLength = Offset(buf.uint64())
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} else {
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headerLength = Offset(buf.uint32())
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}
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r.programOffset = buf.off + headerLength
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r.minInstructionLength = int(buf.uint8())
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if r.version >= 4 {
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// [DWARF4 6.2.4]
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r.maxOpsPerInstruction = int(buf.uint8())
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} else {
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r.maxOpsPerInstruction = 1
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}
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r.defaultIsStmt = buf.uint8() != 0
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r.lineBase = int(int8(buf.uint8()))
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r.lineRange = int(buf.uint8())
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// Validate header.
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if buf.err != nil {
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return buf.err
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}
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if r.maxOpsPerInstruction == 0 {
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return DecodeError{"line", hdrOffset, "invalid maximum operations per instruction: 0"}
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}
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if r.lineRange == 0 {
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return DecodeError{"line", hdrOffset, "invalid line range: 0"}
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}
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// Read standard opcode length table. This table starts with opcode 1.
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r.opcodeBase = int(buf.uint8())
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r.opcodeLengths = make([]int, r.opcodeBase)
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for i := 1; i < r.opcodeBase; i++ {
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r.opcodeLengths[i] = int(buf.uint8())
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}
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// Validate opcode lengths.
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if buf.err != nil {
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return buf.err
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}
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for i, length := range r.opcodeLengths {
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if known, ok := knownOpcodeLengths[i]; ok && known != length {
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return DecodeError{"line", hdrOffset, fmt.Sprintf("opcode %d expected to have length %d, but has length %d", i, known, length)}
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}
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}
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if r.version < 5 {
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// Read include directories table.
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r.directories = []string{compDir}
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for {
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directory := buf.string()
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if buf.err != nil {
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return buf.err
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}
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if len(directory) == 0 {
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break
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}
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if !pathIsAbs(directory) {
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// Relative paths are implicitly relative to
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// the compilation directory.
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directory = pathJoin(compDir, directory)
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}
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r.directories = append(r.directories, directory)
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}
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// Read file name list. File numbering starts with 1,
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// so leave the first entry nil.
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r.fileEntries = make([]*LineFile, 1)
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for {
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if done, err := r.readFileEntry(); err != nil {
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return err
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} else if done {
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break
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}
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}
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} else {
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dirFormat := r.readLNCTFormat()
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c := buf.uint()
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r.directories = make([]string, c)
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for i := range r.directories {
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dir, _, _, err := r.readLNCT(dirFormat, dwarf64)
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if err != nil {
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return err
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}
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r.directories[i] = dir
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}
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fileFormat := r.readLNCTFormat()
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c = buf.uint()
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r.fileEntries = make([]*LineFile, c)
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for i := range r.fileEntries {
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name, mtime, size, err := r.readLNCT(fileFormat, dwarf64)
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if err != nil {
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return err
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}
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r.fileEntries[i] = &LineFile{name, mtime, int(size)}
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}
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}
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r.initialFileEntries = len(r.fileEntries)
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return buf.err
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}
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// lnctForm is a pair of an LNCT code and a form. This represents an
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// entry in the directory name or file name description in the DWARF 5
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// line number program header.
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type lnctForm struct {
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lnct int
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form format
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}
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// readLNCTFormat reads an LNCT format description.
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func (r *LineReader) readLNCTFormat() []lnctForm {
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c := r.buf.uint8()
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ret := make([]lnctForm, c)
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for i := range ret {
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ret[i].lnct = int(r.buf.uint())
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ret[i].form = format(r.buf.uint())
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}
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return ret
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}
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// readLNCT reads a sequence of LNCT entries and returns path information.
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func (r *LineReader) readLNCT(s []lnctForm, dwarf64 bool) (path string, mtime uint64, size uint64, err error) {
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var dir string
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for _, lf := range s {
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var str string
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var val uint64
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switch lf.form {
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case formString:
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str = r.buf.string()
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case formStrp, formLineStrp:
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var off uint64
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if dwarf64 {
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off = r.buf.uint64()
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} else {
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off = uint64(r.buf.uint32())
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}
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if uint64(int(off)) != off {
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return "", 0, 0, DecodeError{"line", r.buf.off, "strp/line_strp offset out of range"}
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}
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var b1 buf
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if lf.form == formStrp {
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b1 = makeBuf(r.buf.dwarf, r.buf.format, "str", 0, r.str)
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} else {
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b1 = makeBuf(r.buf.dwarf, r.buf.format, "line_str", 0, r.lineStr)
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}
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b1.skip(int(off))
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str = b1.string()
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if b1.err != nil {
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return "", 0, 0, DecodeError{"line", r.buf.off, b1.err.Error()}
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}
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case formStrpSup:
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// Supplemental sections not yet supported.
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if dwarf64 {
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r.buf.uint64()
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} else {
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r.buf.uint32()
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}
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case formStrx:
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// .debug_line.dwo sections not yet supported.
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r.buf.uint()
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case formStrx1:
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r.buf.uint8()
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case formStrx2:
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r.buf.uint16()
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case formStrx3:
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r.buf.uint24()
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case formStrx4:
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r.buf.uint32()
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case formData1:
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val = uint64(r.buf.uint8())
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case formData2:
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val = uint64(r.buf.uint16())
|
||
|
|
case formData4:
|
||
|
|
val = uint64(r.buf.uint32())
|
||
|
|
case formData8:
|
||
|
|
val = r.buf.uint64()
|
||
|
|
case formData16:
|
||
|
|
r.buf.bytes(16)
|
||
|
|
case formDwarfBlock:
|
||
|
|
r.buf.bytes(int(r.buf.uint()))
|
||
|
|
case formUdata:
|
||
|
|
val = r.buf.uint()
|
||
|
|
}
|
||
|
|
|
||
|
|
switch lf.lnct {
|
||
|
|
case lnctPath:
|
||
|
|
path = str
|
||
|
|
case lnctDirectoryIndex:
|
||
|
|
if val >= uint64(len(r.directories)) {
|
||
|
|
return "", 0, 0, DecodeError{"line", r.buf.off, "directory index out of range"}
|
||
|
|
}
|
||
|
|
dir = r.directories[val]
|
||
|
|
case lnctTimestamp:
|
||
|
|
mtime = val
|
||
|
|
case lnctSize:
|
||
|
|
size = val
|
||
|
|
case lnctMD5:
|
||
|
|
// Ignored.
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if dir != "" && path != "" {
|
||
|
|
path = pathJoin(dir, path)
|
||
|
|
}
|
||
|
|
|
||
|
|
return path, mtime, size, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// readFileEntry reads a file entry from either the header or a
|
||
|
|
// DW_LNE_define_file extended opcode and adds it to r.fileEntries. A
|
||
|
|
// true return value indicates that there are no more entries to read.
|
||
|
|
func (r *LineReader) readFileEntry() (bool, error) {
|
||
|
|
name := r.buf.string()
|
||
|
|
if r.buf.err != nil {
|
||
|
|
return false, r.buf.err
|
||
|
|
}
|
||
|
|
if len(name) == 0 {
|
||
|
|
return true, nil
|
||
|
|
}
|
||
|
|
off := r.buf.off
|
||
|
|
dirIndex := int(r.buf.uint())
|
||
|
|
if !pathIsAbs(name) {
|
||
|
|
if dirIndex >= len(r.directories) {
|
||
|
|
return false, DecodeError{"line", off, "directory index too large"}
|
||
|
|
}
|
||
|
|
name = pathJoin(r.directories[dirIndex], name)
|
||
|
|
}
|
||
|
|
mtime := r.buf.uint()
|
||
|
|
length := int(r.buf.uint())
|
||
|
|
|
||
|
|
// If this is a dynamically added path and the cursor was
|
||
|
|
// backed up, we may have already added this entry. Avoid
|
||
|
|
// updating existing line table entries in this case. This
|
||
|
|
// avoids an allocation and potential racy access to the slice
|
||
|
|
// backing store if the user called Files.
|
||
|
|
if len(r.fileEntries) < cap(r.fileEntries) {
|
||
|
|
fe := r.fileEntries[:len(r.fileEntries)+1]
|
||
|
|
if fe[len(fe)-1] != nil {
|
||
|
|
// We already processed this addition.
|
||
|
|
r.fileEntries = fe
|
||
|
|
return false, nil
|
||
|
|
}
|
||
|
|
}
|
||
|
|
r.fileEntries = append(r.fileEntries, &LineFile{name, mtime, length})
|
||
|
|
return false, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// updateFile updates r.state.File after r.fileIndex has
|
||
|
|
// changed or r.fileEntries has changed.
|
||
|
|
func (r *LineReader) updateFile() {
|
||
|
|
if r.fileIndex < len(r.fileEntries) {
|
||
|
|
r.state.File = r.fileEntries[r.fileIndex]
|
||
|
|
} else {
|
||
|
|
r.state.File = nil
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Next sets *entry to the next row in this line table and moves to
|
||
|
|
// the next row. If there are no more entries and the line table is
|
||
|
|
// properly terminated, it returns io.EOF.
|
||
|
|
//
|
||
|
|
// Rows are always in order of increasing entry.Address, but
|
||
|
|
// entry.Line may go forward or backward.
|
||
|
|
func (r *LineReader) Next(entry *LineEntry) error {
|
||
|
|
if r.buf.err != nil {
|
||
|
|
return r.buf.err
|
||
|
|
}
|
||
|
|
|
||
|
|
// Execute opcodes until we reach an opcode that emits a line
|
||
|
|
// table entry.
|
||
|
|
for {
|
||
|
|
if len(r.buf.data) == 0 {
|
||
|
|
return io.EOF
|
||
|
|
}
|
||
|
|
emit := r.step(entry)
|
||
|
|
if r.buf.err != nil {
|
||
|
|
return r.buf.err
|
||
|
|
}
|
||
|
|
if emit {
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// knownOpcodeLengths gives the opcode lengths (in varint arguments)
|
||
|
|
// of known standard opcodes.
|
||
|
|
var knownOpcodeLengths = map[int]int{
|
||
|
|
lnsCopy: 0,
|
||
|
|
lnsAdvancePC: 1,
|
||
|
|
lnsAdvanceLine: 1,
|
||
|
|
lnsSetFile: 1,
|
||
|
|
lnsNegateStmt: 0,
|
||
|
|
lnsSetBasicBlock: 0,
|
||
|
|
lnsConstAddPC: 0,
|
||
|
|
lnsSetPrologueEnd: 0,
|
||
|
|
lnsSetEpilogueBegin: 0,
|
||
|
|
lnsSetISA: 1,
|
||
|
|
// lnsFixedAdvancePC takes a uint8 rather than a varint; it's
|
||
|
|
// unclear what length the header is supposed to claim, so
|
||
|
|
// ignore it.
|
||
|
|
}
|
||
|
|
|
||
|
|
// step processes the next opcode and updates r.state. If the opcode
|
||
|
|
// emits a row in the line table, this updates *entry and returns
|
||
|
|
// true.
|
||
|
|
func (r *LineReader) step(entry *LineEntry) bool {
|
||
|
|
opcode := int(r.buf.uint8())
|
||
|
|
|
||
|
|
if opcode >= r.opcodeBase {
|
||
|
|
// Special opcode [DWARF2 6.2.5.1, DWARF4 6.2.5.1]
|
||
|
|
adjustedOpcode := opcode - r.opcodeBase
|
||
|
|
r.advancePC(adjustedOpcode / r.lineRange)
|
||
|
|
lineDelta := r.lineBase + adjustedOpcode%r.lineRange
|
||
|
|
r.state.Line += lineDelta
|
||
|
|
goto emit
|
||
|
|
}
|
||
|
|
|
||
|
|
switch opcode {
|
||
|
|
case 0:
|
||
|
|
// Extended opcode [DWARF2 6.2.5.3]
|
||
|
|
length := Offset(r.buf.uint())
|
||
|
|
startOff := r.buf.off
|
||
|
|
opcode := r.buf.uint8()
|
||
|
|
|
||
|
|
switch opcode {
|
||
|
|
case lneEndSequence:
|
||
|
|
r.state.EndSequence = true
|
||
|
|
*entry = r.state
|
||
|
|
r.resetState()
|
||
|
|
|
||
|
|
case lneSetAddress:
|
||
|
|
switch r.addrsize {
|
||
|
|
case 1:
|
||
|
|
r.state.Address = uint64(r.buf.uint8())
|
||
|
|
case 2:
|
||
|
|
r.state.Address = uint64(r.buf.uint16())
|
||
|
|
case 4:
|
||
|
|
r.state.Address = uint64(r.buf.uint32())
|
||
|
|
case 8:
|
||
|
|
r.state.Address = r.buf.uint64()
|
||
|
|
default:
|
||
|
|
r.buf.error("unknown address size")
|
||
|
|
}
|
||
|
|
|
||
|
|
case lneDefineFile:
|
||
|
|
if done, err := r.readFileEntry(); err != nil {
|
||
|
|
r.buf.err = err
|
||
|
|
return false
|
||
|
|
} else if done {
|
||
|
|
r.buf.err = DecodeError{"line", startOff, "malformed DW_LNE_define_file operation"}
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
r.updateFile()
|
||
|
|
|
||
|
|
case lneSetDiscriminator:
|
||
|
|
// [DWARF4 6.2.5.3]
|
||
|
|
r.state.Discriminator = int(r.buf.uint())
|
||
|
|
}
|
||
|
|
|
||
|
|
r.buf.skip(int(startOff + length - r.buf.off))
|
||
|
|
|
||
|
|
if opcode == lneEndSequence {
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
|
||
|
|
// Standard opcodes [DWARF2 6.2.5.2]
|
||
|
|
case lnsCopy:
|
||
|
|
goto emit
|
||
|
|
|
||
|
|
case lnsAdvancePC:
|
||
|
|
r.advancePC(int(r.buf.uint()))
|
||
|
|
|
||
|
|
case lnsAdvanceLine:
|
||
|
|
r.state.Line += int(r.buf.int())
|
||
|
|
|
||
|
|
case lnsSetFile:
|
||
|
|
r.fileIndex = int(r.buf.uint())
|
||
|
|
r.updateFile()
|
||
|
|
|
||
|
|
case lnsSetColumn:
|
||
|
|
r.state.Column = int(r.buf.uint())
|
||
|
|
|
||
|
|
case lnsNegateStmt:
|
||
|
|
r.state.IsStmt = !r.state.IsStmt
|
||
|
|
|
||
|
|
case lnsSetBasicBlock:
|
||
|
|
r.state.BasicBlock = true
|
||
|
|
|
||
|
|
case lnsConstAddPC:
|
||
|
|
r.advancePC((255 - r.opcodeBase) / r.lineRange)
|
||
|
|
|
||
|
|
case lnsFixedAdvancePC:
|
||
|
|
r.state.Address += uint64(r.buf.uint16())
|
||
|
|
|
||
|
|
// DWARF3 standard opcodes [DWARF3 6.2.5.2]
|
||
|
|
case lnsSetPrologueEnd:
|
||
|
|
r.state.PrologueEnd = true
|
||
|
|
|
||
|
|
case lnsSetEpilogueBegin:
|
||
|
|
r.state.EpilogueBegin = true
|
||
|
|
|
||
|
|
case lnsSetISA:
|
||
|
|
r.state.ISA = int(r.buf.uint())
|
||
|
|
|
||
|
|
default:
|
||
|
|
// Unhandled standard opcode. Skip the number of
|
||
|
|
// arguments that the prologue says this opcode has.
|
||
|
|
for i := 0; i < r.opcodeLengths[opcode]; i++ {
|
||
|
|
r.buf.uint()
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return false
|
||
|
|
|
||
|
|
emit:
|
||
|
|
*entry = r.state
|
||
|
|
r.state.BasicBlock = false
|
||
|
|
r.state.PrologueEnd = false
|
||
|
|
r.state.EpilogueBegin = false
|
||
|
|
r.state.Discriminator = 0
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
|
||
|
|
// advancePC advances "operation pointer" (the combination of Address
|
||
|
|
// and OpIndex) in r.state by opAdvance steps.
|
||
|
|
func (r *LineReader) advancePC(opAdvance int) {
|
||
|
|
opIndex := r.state.OpIndex + opAdvance
|
||
|
|
r.state.Address += uint64(r.minInstructionLength * (opIndex / r.maxOpsPerInstruction))
|
||
|
|
r.state.OpIndex = opIndex % r.maxOpsPerInstruction
|
||
|
|
}
|
||
|
|
|
||
|
|
// A LineReaderPos represents a position in a line table.
|
||
|
|
type LineReaderPos struct {
|
||
|
|
// off is the current offset in the DWARF line section.
|
||
|
|
off Offset
|
||
|
|
// numFileEntries is the length of fileEntries.
|
||
|
|
numFileEntries int
|
||
|
|
// state and fileIndex are the statement machine state at
|
||
|
|
// offset off.
|
||
|
|
state LineEntry
|
||
|
|
fileIndex int
|
||
|
|
}
|
||
|
|
|
||
|
|
// Tell returns the current position in the line table.
|
||
|
|
func (r *LineReader) Tell() LineReaderPos {
|
||
|
|
return LineReaderPos{r.buf.off, len(r.fileEntries), r.state, r.fileIndex}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Seek restores the line table reader to a position returned by Tell.
|
||
|
|
//
|
||
|
|
// The argument pos must have been returned by a call to Tell on this
|
||
|
|
// line table.
|
||
|
|
func (r *LineReader) Seek(pos LineReaderPos) {
|
||
|
|
r.buf.off = pos.off
|
||
|
|
r.buf.data = r.section[r.buf.off:r.endOffset]
|
||
|
|
r.fileEntries = r.fileEntries[:pos.numFileEntries]
|
||
|
|
r.state = pos.state
|
||
|
|
r.fileIndex = pos.fileIndex
|
||
|
|
}
|
||
|
|
|
||
|
|
// Reset repositions the line table reader at the beginning of the
|
||
|
|
// line table.
|
||
|
|
func (r *LineReader) Reset() {
|
||
|
|
// Reset buffer to the line number program offset.
|
||
|
|
r.buf.off = r.programOffset
|
||
|
|
r.buf.data = r.section[r.buf.off:r.endOffset]
|
||
|
|
|
||
|
|
// Reset file entries list.
|
||
|
|
r.fileEntries = r.fileEntries[:r.initialFileEntries]
|
||
|
|
|
||
|
|
// Reset line number program state.
|
||
|
|
r.resetState()
|
||
|
|
}
|
||
|
|
|
||
|
|
// resetState resets r.state to its default values
|
||
|
|
func (r *LineReader) resetState() {
|
||
|
|
// Reset the state machine registers to the defaults given in
|
||
|
|
// [DWARF4 6.2.2].
|
||
|
|
r.state = LineEntry{
|
||
|
|
Address: 0,
|
||
|
|
OpIndex: 0,
|
||
|
|
File: nil,
|
||
|
|
Line: 1,
|
||
|
|
Column: 0,
|
||
|
|
IsStmt: r.defaultIsStmt,
|
||
|
|
BasicBlock: false,
|
||
|
|
PrologueEnd: false,
|
||
|
|
EpilogueBegin: false,
|
||
|
|
ISA: 0,
|
||
|
|
Discriminator: 0,
|
||
|
|
}
|
||
|
|
r.fileIndex = 1
|
||
|
|
r.updateFile()
|
||
|
|
}
|
||
|
|
|
||
|
|
// Files returns the file name table of this compilation unit as of
|
||
|
|
// the current position in the line table. The file name table may be
|
||
|
|
// referenced from attributes in this compilation unit such as
|
||
|
|
// AttrDeclFile.
|
||
|
|
//
|
||
|
|
// Entry 0 is always nil, since file index 0 represents "no file".
|
||
|
|
//
|
||
|
|
// The file name table of a compilation unit is not fixed. Files
|
||
|
|
// returns the file table as of the current position in the line
|
||
|
|
// table. This may contain more entries than the file table at an
|
||
|
|
// earlier position in the line table, though existing entries never
|
||
|
|
// change.
|
||
|
|
func (r *LineReader) Files() []*LineFile {
|
||
|
|
return r.fileEntries
|
||
|
|
}
|
||
|
|
|
||
|
|
// ErrUnknownPC is the error returned by LineReader.ScanPC when the
|
||
|
|
// seek PC is not covered by any entry in the line table.
|
||
|
|
var ErrUnknownPC = errors.New("ErrUnknownPC")
|
||
|
|
|
||
|
|
// SeekPC sets *entry to the LineEntry that includes pc and positions
|
||
|
|
// the reader on the next entry in the line table. If necessary, this
|
||
|
|
// will seek backwards to find pc.
|
||
|
|
//
|
||
|
|
// If pc is not covered by any entry in this line table, SeekPC
|
||
|
|
// returns ErrUnknownPC. In this case, *entry and the final seek
|
||
|
|
// position are unspecified.
|
||
|
|
//
|
||
|
|
// Note that DWARF line tables only permit sequential, forward scans.
|
||
|
|
// Hence, in the worst case, this takes time linear in the size of the
|
||
|
|
// line table. If the caller wishes to do repeated fast PC lookups, it
|
||
|
|
// should build an appropriate index of the line table.
|
||
|
|
func (r *LineReader) SeekPC(pc uint64, entry *LineEntry) error {
|
||
|
|
if err := r.Next(entry); err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
if entry.Address > pc {
|
||
|
|
// We're too far. Start at the beginning of the table.
|
||
|
|
r.Reset()
|
||
|
|
if err := r.Next(entry); err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
if entry.Address > pc {
|
||
|
|
// The whole table starts after pc.
|
||
|
|
r.Reset()
|
||
|
|
return ErrUnknownPC
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Scan until we pass pc, then back up one.
|
||
|
|
for {
|
||
|
|
var next LineEntry
|
||
|
|
pos := r.Tell()
|
||
|
|
if err := r.Next(&next); err != nil {
|
||
|
|
if err == io.EOF {
|
||
|
|
return ErrUnknownPC
|
||
|
|
}
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
if next.Address > pc {
|
||
|
|
if entry.EndSequence {
|
||
|
|
// pc is in a hole in the table.
|
||
|
|
return ErrUnknownPC
|
||
|
|
}
|
||
|
|
// entry is the desired entry. Back up the
|
||
|
|
// cursor to "next" and return success.
|
||
|
|
r.Seek(pos)
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
*entry = next
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// pathIsAbs reports whether path is an absolute path (or "full path
|
||
|
|
// name" in DWARF parlance). This is in "whatever form makes sense for
|
||
|
|
// the host system", so this accepts both UNIX-style and DOS-style
|
||
|
|
// absolute paths. We avoid the filepath package because we want this
|
||
|
|
// to behave the same regardless of our host system and because we
|
||
|
|
// don't know what system the paths came from.
|
||
|
|
func pathIsAbs(path string) bool {
|
||
|
|
_, path = splitDrive(path)
|
||
|
|
return len(path) > 0 && (path[0] == '/' || path[0] == '\\')
|
||
|
|
}
|
||
|
|
|
||
|
|
// pathJoin joins dirname and filename. filename must be relative.
|
||
|
|
// DWARF paths can be UNIX-style or DOS-style, so this handles both.
|
||
|
|
func pathJoin(dirname, filename string) string {
|
||
|
|
if len(dirname) == 0 {
|
||
|
|
return filename
|
||
|
|
}
|
||
|
|
// dirname should be absolute, which means we can determine
|
||
|
|
// whether it's a DOS path reasonably reliably by looking for
|
||
|
|
// a drive letter or UNC path.
|
||
|
|
drive, dirname := splitDrive(dirname)
|
||
|
|
if drive == "" {
|
||
|
|
// UNIX-style path.
|
||
|
|
return path.Join(dirname, filename)
|
||
|
|
}
|
||
|
|
// DOS-style path.
|
||
|
|
drive2, filename := splitDrive(filename)
|
||
|
|
if drive2 != "" {
|
||
|
|
if !strings.EqualFold(drive, drive2) {
|
||
|
|
// Different drives. There's not much we can
|
||
|
|
// do here, so just ignore the directory.
|
||
|
|
return drive2 + filename
|
||
|
|
}
|
||
|
|
// Drives are the same. Ignore drive on filename.
|
||
|
|
}
|
||
|
|
if !(strings.HasSuffix(dirname, "/") || strings.HasSuffix(dirname, `\`)) && dirname != "" {
|
||
|
|
sep := `\`
|
||
|
|
if strings.HasPrefix(dirname, "/") {
|
||
|
|
sep = `/`
|
||
|
|
}
|
||
|
|
dirname += sep
|
||
|
|
}
|
||
|
|
return drive + dirname + filename
|
||
|
|
}
|
||
|
|
|
||
|
|
// splitDrive splits the DOS drive letter or UNC share point from
|
||
|
|
// path, if any. path == drive + rest
|
||
|
|
func splitDrive(path string) (drive, rest string) {
|
||
|
|
if len(path) >= 2 && path[1] == ':' {
|
||
|
|
if c := path[0]; 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' {
|
||
|
|
return path[:2], path[2:]
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if len(path) > 3 && (path[0] == '\\' || path[0] == '/') && (path[1] == '\\' || path[1] == '/') {
|
||
|
|
// Normalize the path so we can search for just \ below.
|
||
|
|
npath := strings.Replace(path, "/", `\`, -1)
|
||
|
|
// Get the host part, which must be non-empty.
|
||
|
|
slash1 := strings.IndexByte(npath[2:], '\\') + 2
|
||
|
|
if slash1 > 2 {
|
||
|
|
// Get the mount-point part, which must be non-empty.
|
||
|
|
slash2 := strings.IndexByte(npath[slash1+1:], '\\') + slash1 + 1
|
||
|
|
if slash2 > slash1 {
|
||
|
|
return path[:slash2], path[slash2:]
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return "", path
|
||
|
|
}
|