Adding upstream version 1.20.14.upstream/1.20.14upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 695 insertions, 0 deletions

diff --git a/src/debug/gosym/pclntab.go b/src/debug/gosym/pclntab.go
new file mode 100644
index 0000000..a87e6cf
--- /dev/null
+++ b/src/debug/gosym/pclntab.go
@@ -0,0 +1,695 @@
+// 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.
+
+/*
+ * Line tables
+ */
+
+package gosym
+
+import (
+	"bytes"
+	"encoding/binary"
+	"sort"
+	"sync"
+)
+
+// version of the pclntab
+type version int
+
+const (
+	verUnknown version = iota
+	ver11
+	ver12
+	ver116
+	ver118
+	ver120
+)
+
+// A LineTable is a data structure mapping program counters to line numbers.
+//
+// In Go 1.1 and earlier, each function (represented by a Func) had its own LineTable,
+// and the line number corresponded to a numbering of all source lines in the
+// program, across all files. That absolute line number would then have to be
+// converted separately to a file name and line number within the file.
+//
+// In Go 1.2, the format of the data changed so that there is a single LineTable
+// for the entire program, shared by all Funcs, and there are no absolute line
+// numbers, just line numbers within specific files.
+//
+// For the most part, LineTable's methods should be treated as an internal
+// detail of the package; callers should use the methods on Table instead.
+type LineTable struct {
+	Data []byte
+	PC   uint64
+	Line int
+
+	// This mutex is used to keep parsing of pclntab synchronous.
+	mu sync.Mutex
+
+	// Contains the version of the pclntab section.
+	version version
+
+	// Go 1.2/1.16/1.18 state
+	binary      binary.ByteOrder
+	quantum     uint32
+	ptrsize     uint32
+	textStart   uint64 // address of runtime.text symbol (1.18+)
+	funcnametab []byte
+	cutab       []byte
+	funcdata    []byte
+	functab     []byte
+	nfunctab    uint32
+	filetab     []byte
+	pctab       []byte // points to the pctables.
+	nfiletab    uint32
+	funcNames   map[uint32]string // cache the function names
+	strings     map[uint32]string // interned substrings of Data, keyed by offset
+	// fileMap varies depending on the version of the object file.
+	// For ver12, it maps the name to the index in the file table.
+	// For ver116, it maps the name to the offset in filetab.
+	fileMap map[string]uint32
+}
+
+// NOTE(rsc): This is wrong for GOARCH=arm, which uses a quantum of 4,
+// but we have no idea whether we're using arm or not. This only
+// matters in the old (pre-Go 1.2) symbol table format, so it's not worth
+// fixing.
+const oldQuantum = 1
+
+func (t *LineTable) parse(targetPC uint64, targetLine int) (b []byte, pc uint64, line int) {
+	// The PC/line table can be thought of as a sequence of
+	//  <pc update>* <line update>
+	// batches. Each update batch results in a (pc, line) pair,
+	// where line applies to every PC from pc up to but not
+	// including the pc of the next pair.
+	//
+	// Here we process each update individually, which simplifies
+	// the code, but makes the corner cases more confusing.
+	b, pc, line = t.Data, t.PC, t.Line
+	for pc <= targetPC && line != targetLine && len(b) > 0 {
+		code := b[0]
+		b = b[1:]
+		switch {
+		case code == 0:
+			if len(b) < 4 {
+				b = b[0:0]
+				break
+			}
+			val := binary.BigEndian.Uint32(b)
+			b = b[4:]
+			line += int(val)
+		case code <= 64:
+			line += int(code)
+		case code <= 128:
+			line -= int(code - 64)
+		default:
+			pc += oldQuantum * uint64(code-128)
+			continue
+		}
+		pc += oldQuantum
+	}
+	return b, pc, line
+}
+
+func (t *LineTable) slice(pc uint64) *LineTable {
+	data, pc, line := t.parse(pc, -1)
+	return &LineTable{Data: data, PC: pc, Line: line}
+}
+
+// PCToLine returns the line number for the given program counter.
+//
+// Deprecated: Use Table's PCToLine method instead.
+func (t *LineTable) PCToLine(pc uint64) int {
+	if t.isGo12() {
+		return t.go12PCToLine(pc)
+	}
+	_, _, line := t.parse(pc, -1)
+	return line
+}
+
+// LineToPC returns the program counter for the given line number,
+// considering only program counters before maxpc.
+//
+// Deprecated: Use Table's LineToPC method instead.
+func (t *LineTable) LineToPC(line int, maxpc uint64) uint64 {
+	if t.isGo12() {
+		return 0
+	}
+	_, pc, line1 := t.parse(maxpc, line)
+	if line1 != line {
+		return 0
+	}
+	// Subtract quantum from PC to account for post-line increment
+	return pc - oldQuantum
+}
+
+// NewLineTable returns a new PC/line table
+// corresponding to the encoded data.
+// Text must be the start address of the
+// corresponding text segment.
+func NewLineTable(data []byte, text uint64) *LineTable {
+	return &LineTable{Data: data, PC: text, Line: 0, funcNames: make(map[uint32]string), strings: make(map[uint32]string)}
+}
+
+// Go 1.2 symbol table format.
+// See golang.org/s/go12symtab.
+//
+// A general note about the methods here: rather than try to avoid
+// index out of bounds errors, we trust Go to detect them, and then
+// we recover from the panics and treat them as indicative of a malformed
+// or incomplete table.
+//
+// The methods called by symtab.go, which begin with "go12" prefixes,
+// are expected to have that recovery logic.
+
+// isGo12 reports whether this is a Go 1.2 (or later) symbol table.
+func (t *LineTable) isGo12() bool {
+	t.parsePclnTab()
+	return t.version >= ver12
+}
+
+const (
+	go12magic  = 0xfffffffb
+	go116magic = 0xfffffffa
+	go118magic = 0xfffffff0
+	go120magic = 0xfffffff1
+)
+
+// uintptr returns the pointer-sized value encoded at b.
+// The pointer size is dictated by the table being read.
+func (t *LineTable) uintptr(b []byte) uint64 {
+	if t.ptrsize == 4 {
+		return uint64(t.binary.Uint32(b))
+	}
+	return t.binary.Uint64(b)
+}
+
+// parsePclnTab parses the pclntab, setting the version.
+func (t *LineTable) parsePclnTab() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	if t.version != verUnknown {
+		return
+	}
+
+	// Note that during this function, setting the version is the last thing we do.
+	// If we set the version too early, and parsing failed (likely as a panic on
+	// slice lookups), we'd have a mistaken version.
+	//
+	// Error paths through this code will default the version to 1.1.
+	t.version = ver11
+
+	if !disableRecover {
+		defer func() {
+			// If we panic parsing, assume it's a Go 1.1 pclntab.
+			recover()
+		}()
+	}
+
+	// Check header: 4-byte magic, two zeros, pc quantum, pointer size.
+	if len(t.Data) < 16 || t.Data[4] != 0 || t.Data[5] != 0 ||
+		(t.Data[6] != 1 && t.Data[6] != 2 && t.Data[6] != 4) || // pc quantum
+		(t.Data[7] != 4 && t.Data[7] != 8) { // pointer size
+		return
+	}
+
+	var possibleVersion version
+	leMagic := binary.LittleEndian.Uint32(t.Data)
+	beMagic := binary.BigEndian.Uint32(t.Data)
+	switch {
+	case leMagic == go12magic:
+		t.binary, possibleVersion = binary.LittleEndian, ver12
+	case beMagic == go12magic:
+		t.binary, possibleVersion = binary.BigEndian, ver12
+	case leMagic == go116magic:
+		t.binary, possibleVersion = binary.LittleEndian, ver116
+	case beMagic == go116magic:
+		t.binary, possibleVersion = binary.BigEndian, ver116
+	case leMagic == go118magic:
+		t.binary, possibleVersion = binary.LittleEndian, ver118
+	case beMagic == go118magic:
+		t.binary, possibleVersion = binary.BigEndian, ver118
+	case leMagic == go120magic:
+		t.binary, possibleVersion = binary.LittleEndian, ver120
+	case beMagic == go120magic:
+		t.binary, possibleVersion = binary.BigEndian, ver120
+	default:
+		return
+	}
+	t.version = possibleVersion
+
+	// quantum and ptrSize are the same between 1.2, 1.16, and 1.18
+	t.quantum = uint32(t.Data[6])
+	t.ptrsize = uint32(t.Data[7])
+
+	offset := func(word uint32) uint64 {
+		return t.uintptr(t.Data[8+word*t.ptrsize:])
+	}
+	data := func(word uint32) []byte {
+		return t.Data[offset(word):]
+	}
+
+	switch possibleVersion {
+	case ver118, ver120:
+		t.nfunctab = uint32(offset(0))
+		t.nfiletab = uint32(offset(1))
+		t.textStart = t.PC // use the start PC instead of reading from the table, which may be unrelocated
+		t.funcnametab = data(3)
+		t.cutab = data(4)
+		t.filetab = data(5)
+		t.pctab = data(6)
+		t.funcdata = data(7)
+		t.functab = data(7)
+		functabsize := (int(t.nfunctab)*2 + 1) * t.functabFieldSize()
+		t.functab = t.functab[:functabsize]
+	case ver116:
+		t.nfunctab = uint32(offset(0))
+		t.nfiletab = uint32(offset(1))
+		t.funcnametab = data(2)
+		t.cutab = data(3)
+		t.filetab = data(4)
+		t.pctab = data(5)
+		t.funcdata = data(6)
+		t.functab = data(6)
+		functabsize := (int(t.nfunctab)*2 + 1) * t.functabFieldSize()
+		t.functab = t.functab[:functabsize]
+	case ver12:
+		t.nfunctab = uint32(t.uintptr(t.Data[8:]))
+		t.funcdata = t.Data
+		t.funcnametab = t.Data
+		t.functab = t.Data[8+t.ptrsize:]
+		t.pctab = t.Data
+		functabsize := (int(t.nfunctab)*2 + 1) * t.functabFieldSize()
+		fileoff := t.binary.Uint32(t.functab[functabsize:])
+		t.functab = t.functab[:functabsize]
+		t.filetab = t.Data[fileoff:]
+		t.nfiletab = t.binary.Uint32(t.filetab)
+		t.filetab = t.filetab[:t.nfiletab*4]
+	default:
+		panic("unreachable")
+	}
+}
+
+// go12Funcs returns a slice of Funcs derived from the Go 1.2+ pcln table.
+func (t *LineTable) go12Funcs() []Func {
+	// Assume it is malformed and return nil on error.
+	if !disableRecover {
+		defer func() {
+			recover()
+		}()
+	}
+
+	ft := t.funcTab()
+	funcs := make([]Func, ft.Count())
+	syms := make([]Sym, len(funcs))
+	for i := range funcs {
+		f := &funcs[i]
+		f.Entry = ft.pc(i)
+		f.End = ft.pc(i + 1)
+		info := t.funcData(uint32(i))
+		f.LineTable = t
+		f.FrameSize = int(info.deferreturn())
+		syms[i] = Sym{
+			Value:     f.Entry,
+			Type:      'T',
+			Name:      t.funcName(info.nameOff()),
+			GoType:    0,
+			Func:      f,
+			goVersion: t.version,
+		}
+		f.Sym = &syms[i]
+	}
+	return funcs
+}
+
+// findFunc returns the funcData corresponding to the given program counter.
+func (t *LineTable) findFunc(pc uint64) funcData {
+	ft := t.funcTab()
+	if pc < ft.pc(0) || pc >= ft.pc(ft.Count()) {
+		return funcData{}
+	}
+	idx := sort.Search(int(t.nfunctab), func(i int) bool {
+		return ft.pc(i) > pc
+	})
+	idx--
+	return t.funcData(uint32(idx))
+}
+
+// readvarint reads, removes, and returns a varint from *pp.
+func (t *LineTable) readvarint(pp *[]byte) uint32 {
+	var v, shift uint32
+	p := *pp
+	for shift = 0; ; shift += 7 {
+		b := p[0]
+		p = p[1:]
+		v |= (uint32(b) & 0x7F) << shift
+		if b&0x80 == 0 {
+			break
+		}
+	}
+	*pp = p
+	return v
+}
+
+// funcName returns the name of the function found at off.
+func (t *LineTable) funcName(off uint32) string {
+	if s, ok := t.funcNames[off]; ok {
+		return s
+	}
+	i := bytes.IndexByte(t.funcnametab[off:], 0)
+	s := string(t.funcnametab[off : off+uint32(i)])
+	t.funcNames[off] = s
+	return s
+}
+
+// stringFrom returns a Go string found at off from a position.
+func (t *LineTable) stringFrom(arr []byte, off uint32) string {
+	if s, ok := t.strings[off]; ok {
+		return s
+	}
+	i := bytes.IndexByte(arr[off:], 0)
+	s := string(arr[off : off+uint32(i)])
+	t.strings[off] = s
+	return s
+}
+
+// string returns a Go string found at off.
+func (t *LineTable) string(off uint32) string {
+	return t.stringFrom(t.funcdata, off)
+}
+
+// functabFieldSize returns the size in bytes of a single functab field.
+func (t *LineTable) functabFieldSize() int {
+	if t.version >= ver118 {
+		return 4
+	}
+	return int(t.ptrsize)
+}
+
+// funcTab returns t's funcTab.
+func (t *LineTable) funcTab() funcTab {
+	return funcTab{LineTable: t, sz: t.functabFieldSize()}
+}
+
+// funcTab is memory corresponding to a slice of functab structs, followed by an invalid PC.
+// A functab struct is a PC and a func offset.
+type funcTab struct {
+	*LineTable
+	sz int // cached result of t.functabFieldSize
+}
+
+// Count returns the number of func entries in f.
+func (f funcTab) Count() int {
+	return int(f.nfunctab)
+}
+
+// pc returns the PC of the i'th func in f.
+func (f funcTab) pc(i int) uint64 {
+	u := f.uint(f.functab[2*i*f.sz:])
+	if f.version >= ver118 {
+		u += f.textStart
+	}
+	return u
+}
+
+// funcOff returns the funcdata offset of the i'th func in f.
+func (f funcTab) funcOff(i int) uint64 {
+	return f.uint(f.functab[(2*i+1)*f.sz:])
+}
+
+// uint returns the uint stored at b.
+func (f funcTab) uint(b []byte) uint64 {
+	if f.sz == 4 {
+		return uint64(f.binary.Uint32(b))
+	}
+	return f.binary.Uint64(b)
+}
+
+// funcData is memory corresponding to an _func struct.
+type funcData struct {
+	t    *LineTable // LineTable this data is a part of
+	data []byte     // raw memory for the function
+}
+
+// funcData returns the ith funcData in t.functab.
+func (t *LineTable) funcData(i uint32) funcData {
+	data := t.funcdata[t.funcTab().funcOff(int(i)):]
+	return funcData{t: t, data: data}
+}
+
+// IsZero reports whether f is the zero value.
+func (f funcData) IsZero() bool {
+	return f.t == nil && f.data == nil
+}
+
+// entryPC returns the func's entry PC.
+func (f *funcData) entryPC() uint64 {
+	// In Go 1.18, the first field of _func changed
+	// from a uintptr entry PC to a uint32 entry offset.
+	if f.t.version >= ver118 {
+		// TODO: support multiple text sections.
+		// See runtime/symtab.go:(*moduledata).textAddr.
+		return uint64(f.t.binary.Uint32(f.data)) + f.t.textStart
+	}
+	return f.t.uintptr(f.data)
+}
+
+func (f funcData) nameOff() uint32     { return f.field(1) }
+func (f funcData) deferreturn() uint32 { return f.field(3) }
+func (f funcData) pcfile() uint32      { return f.field(5) }
+func (f funcData) pcln() uint32        { return f.field(6) }
+func (f funcData) cuOffset() uint32    { return f.field(8) }
+
+// field returns the nth field of the _func struct.
+// It panics if n == 0 or n > 9; for n == 0, call f.entryPC.
+// Most callers should use a named field accessor (just above).
+func (f funcData) field(n uint32) uint32 {
+	if n == 0 || n > 9 {
+		panic("bad funcdata field")
+	}
+	// In Go 1.18, the first field of _func changed
+	// from a uintptr entry PC to a uint32 entry offset.
+	sz0 := f.t.ptrsize
+	if f.t.version >= ver118 {
+		sz0 = 4
+	}
+	off := sz0 + (n-1)*4 // subsequent fields are 4 bytes each
+	data := f.data[off:]
+	return f.t.binary.Uint32(data)
+}
+
+// step advances to the next pc, value pair in the encoded table.
+func (t *LineTable) step(p *[]byte, pc *uint64, val *int32, first bool) bool {
+	uvdelta := t.readvarint(p)
+	if uvdelta == 0 && !first {
+		return false
+	}
+	if uvdelta&1 != 0 {
+		uvdelta = ^(uvdelta >> 1)
+	} else {
+		uvdelta >>= 1
+	}
+	vdelta := int32(uvdelta)
+	pcdelta := t.readvarint(p) * t.quantum
+	*pc += uint64(pcdelta)
+	*val += vdelta
+	return true
+}
+
+// pcvalue reports the value associated with the target pc.
+// off is the offset to the beginning of the pc-value table,
+// and entry is the start PC for the corresponding function.
+func (t *LineTable) pcvalue(off uint32, entry, targetpc uint64) int32 {
+	p := t.pctab[off:]
+
+	val := int32(-1)
+	pc := entry
+	for t.step(&p, &pc, &val, pc == entry) {
+		if targetpc < pc {
+			return val
+		}
+	}
+	return -1
+}
+
+// findFileLine scans one function in the binary looking for a
+// program counter in the given file on the given line.
+// It does so by running the pc-value tables mapping program counter
+// to file number. Since most functions come from a single file, these
+// are usually short and quick to scan. If a file match is found, then the
+// code goes to the expense of looking for a simultaneous line number match.
+func (t *LineTable) findFileLine(entry uint64, filetab, linetab uint32, filenum, line int32, cutab []byte) uint64 {
+	if filetab == 0 || linetab == 0 {
+		return 0
+	}
+
+	fp := t.pctab[filetab:]
+	fl := t.pctab[linetab:]
+	fileVal := int32(-1)
+	filePC := entry
+	lineVal := int32(-1)
+	linePC := entry
+	fileStartPC := filePC
+	for t.step(&fp, &filePC, &fileVal, filePC == entry) {
+		fileIndex := fileVal
+		if t.version == ver116 || t.version == ver118 || t.version == ver120 {
+			fileIndex = int32(t.binary.Uint32(cutab[fileVal*4:]))
+		}
+		if fileIndex == filenum && fileStartPC < filePC {
+			// fileIndex is in effect starting at fileStartPC up to
+			// but not including filePC, and it's the file we want.
+			// Run the PC table looking for a matching line number
+			// or until we reach filePC.
+			lineStartPC := linePC
+			for linePC < filePC && t.step(&fl, &linePC, &lineVal, linePC == entry) {
+				// lineVal is in effect until linePC, and lineStartPC < filePC.
+				if lineVal == line {
+					if fileStartPC <= lineStartPC {
+						return lineStartPC
+					}
+					if fileStartPC < linePC {
+						return fileStartPC
+					}
+				}
+				lineStartPC = linePC
+			}
+		}
+		fileStartPC = filePC
+	}
+	return 0
+}
+
+// go12PCToLine maps program counter to line number for the Go 1.2+ pcln table.
+func (t *LineTable) go12PCToLine(pc uint64) (line int) {
+	defer func() {
+		if !disableRecover && recover() != nil {
+			line = -1
+		}
+	}()
+
+	f := t.findFunc(pc)
+	if f.IsZero() {
+		return -1
+	}
+	entry := f.entryPC()
+	linetab := f.pcln()
+	return int(t.pcvalue(linetab, entry, pc))
+}
+
+// go12PCToFile maps program counter to file name for the Go 1.2+ pcln table.
+func (t *LineTable) go12PCToFile(pc uint64) (file string) {
+	defer func() {
+		if !disableRecover && recover() != nil {
+			file = ""
+		}
+	}()
+
+	f := t.findFunc(pc)
+	if f.IsZero() {
+		return ""
+	}
+	entry := f.entryPC()
+	filetab := f.pcfile()
+	fno := t.pcvalue(filetab, entry, pc)
+	if t.version == ver12 {
+		if fno <= 0 {
+			return ""
+		}
+		return t.string(t.binary.Uint32(t.filetab[4*fno:]))
+	}
+	// Go ≥ 1.16
+	if fno < 0 { // 0 is valid for ≥ 1.16
+		return ""
+	}
+	cuoff := f.cuOffset()
+	if fnoff := t.binary.Uint32(t.cutab[(cuoff+uint32(fno))*4:]); fnoff != ^uint32(0) {
+		return t.stringFrom(t.filetab, fnoff)
+	}
+	return ""
+}
+
+// go12LineToPC maps a (file, line) pair to a program counter for the Go 1.2+ pcln table.
+func (t *LineTable) go12LineToPC(file string, line int) (pc uint64) {
+	defer func() {
+		if !disableRecover && recover() != nil {
+			pc = 0
+		}
+	}()
+
+	t.initFileMap()
+	filenum, ok := t.fileMap[file]
+	if !ok {
+		return 0
+	}
+
+	// Scan all functions.
+	// If this turns out to be a bottleneck, we could build a map[int32][]int32
+	// mapping file number to a list of functions with code from that file.
+	var cutab []byte
+	for i := uint32(0); i < t.nfunctab; i++ {
+		f := t.funcData(i)
+		entry := f.entryPC()
+		filetab := f.pcfile()
+		linetab := f.pcln()
+		if t.version == ver116 || t.version == ver118 || t.version == ver120 {
+			if f.cuOffset() == ^uint32(0) {
+				// skip functions without compilation unit (not real function, or linker generated)
+				continue
+			}
+			cutab = t.cutab[f.cuOffset()*4:]
+		}
+		pc := t.findFileLine(entry, filetab, linetab, int32(filenum), int32(line), cutab)
+		if pc != 0 {
+			return pc
+		}
+	}
+	return 0
+}
+
+// initFileMap initializes the map from file name to file number.
+func (t *LineTable) initFileMap() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	if t.fileMap != nil {
+		return
+	}
+	m := make(map[string]uint32)
+
+	if t.version == ver12 {
+		for i := uint32(1); i < t.nfiletab; i++ {
+			s := t.string(t.binary.Uint32(t.filetab[4*i:]))
+			m[s] = i
+		}
+	} else {
+		var pos uint32
+		for i := uint32(0); i < t.nfiletab; i++ {
+			s := t.stringFrom(t.filetab, pos)
+			m[s] = pos
+			pos += uint32(len(s) + 1)
+		}
+	}
+	t.fileMap = m
+}
+
+// go12MapFiles adds to m a key for every file in the Go 1.2 LineTable.
+// Every key maps to obj. That's not a very interesting map, but it provides
+// a way for callers to obtain the list of files in the program.
+func (t *LineTable) go12MapFiles(m map[string]*Obj, obj *Obj) {
+	if !disableRecover {
+		defer func() {
+			recover()
+		}()
+	}
+
+	t.initFileMap()
+	for file := range t.fileMap {
+		m[file] = obj
+	}
+}
+
+// disableRecover causes this package not to swallow panics.
+// This is useful when making changes.
+const disableRecover = false