Adding upstream version 1.16.10.upstream/1.16.10upstream

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

1 files changed, 409 insertions, 0 deletions

diff --git a/src/cmd/internal/objfile/disasm.go b/src/cmd/internal/objfile/disasm.go
new file mode 100644
index 0000000..b5f1cd1
--- /dev/null
+++ b/src/cmd/internal/objfile/disasm.go
@@ -0,0 +1,409 @@
+// Copyright 2014 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 objfile
+
+import (
+	"bufio"
+	"bytes"
+	"cmd/internal/src"
+	"container/list"
+	"debug/gosym"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strings"
+	"text/tabwriter"
+
+	"golang.org/x/arch/arm/armasm"
+	"golang.org/x/arch/arm64/arm64asm"
+	"golang.org/x/arch/ppc64/ppc64asm"
+	"golang.org/x/arch/x86/x86asm"
+)
+
+// Disasm is a disassembler for a given File.
+type Disasm struct {
+	syms      []Sym            //symbols in file, sorted by address
+	pcln      Liner            // pcln table
+	text      []byte           // bytes of text segment (actual instructions)
+	textStart uint64           // start PC of text
+	textEnd   uint64           // end PC of text
+	goarch    string           // GOARCH string
+	disasm    disasmFunc       // disassembler function for goarch
+	byteOrder binary.ByteOrder // byte order for goarch
+}
+
+// Disasm returns a disassembler for the file f.
+func (e *Entry) Disasm() (*Disasm, error) {
+	syms, err := e.Symbols()
+	if err != nil {
+		return nil, err
+	}
+
+	pcln, err := e.PCLineTable()
+	if err != nil {
+		return nil, err
+	}
+
+	textStart, textBytes, err := e.Text()
+	if err != nil {
+		return nil, err
+	}
+
+	goarch := e.GOARCH()
+	disasm := disasms[goarch]
+	byteOrder := byteOrders[goarch]
+	if disasm == nil || byteOrder == nil {
+		return nil, fmt.Errorf("unsupported architecture")
+	}
+
+	// Filter out section symbols, overwriting syms in place.
+	keep := syms[:0]
+	for _, sym := range syms {
+		switch sym.Name {
+		case "runtime.text", "text", "_text", "runtime.etext", "etext", "_etext":
+			// drop
+		default:
+			keep = append(keep, sym)
+		}
+	}
+	syms = keep
+	d := &Disasm{
+		syms:      syms,
+		pcln:      pcln,
+		text:      textBytes,
+		textStart: textStart,
+		textEnd:   textStart + uint64(len(textBytes)),
+		goarch:    goarch,
+		disasm:    disasm,
+		byteOrder: byteOrder,
+	}
+
+	return d, nil
+}
+
+// lookup finds the symbol name containing addr.
+func (d *Disasm) lookup(addr uint64) (name string, base uint64) {
+	i := sort.Search(len(d.syms), func(i int) bool { return addr < d.syms[i].Addr })
+	if i > 0 {
+		s := d.syms[i-1]
+		if s.Addr != 0 && s.Addr <= addr && addr < s.Addr+uint64(s.Size) {
+			return s.Name, s.Addr
+		}
+	}
+	return "", 0
+}
+
+// base returns the final element in the path.
+// It works on both Windows and Unix paths,
+// regardless of host operating system.
+func base(path string) string {
+	path = path[strings.LastIndex(path, "/")+1:]
+	path = path[strings.LastIndex(path, `\`)+1:]
+	return path
+}
+
+// CachedFile contains the content of a file split into lines.
+type CachedFile struct {
+	FileName string
+	Lines    [][]byte
+}
+
+// FileCache is a simple LRU cache of file contents.
+type FileCache struct {
+	files  *list.List
+	maxLen int
+}
+
+// NewFileCache returns a FileCache which can contain up to maxLen cached file contents.
+func NewFileCache(maxLen int) *FileCache {
+	return &FileCache{
+		files:  list.New(),
+		maxLen: maxLen,
+	}
+}
+
+// Line returns the source code line for the given file and line number.
+// If the file is not already cached, reads it, inserts it into the cache,
+// and removes the least recently used file if necessary.
+// If the file is in cache, it is moved to the front of the list.
+func (fc *FileCache) Line(filename string, line int) ([]byte, error) {
+	if filepath.Ext(filename) != ".go" {
+		return nil, nil
+	}
+
+	// Clean filenames returned by src.Pos.SymFilename()
+	// or src.PosBase.SymFilename() removing
+	// the leading src.FileSymPrefix.
+	filename = strings.TrimPrefix(filename, src.FileSymPrefix)
+
+	// Expand literal "$GOROOT" rewritten by obj.AbsFile()
+	filename = filepath.Clean(os.ExpandEnv(filename))
+
+	var cf *CachedFile
+	var e *list.Element
+
+	for e = fc.files.Front(); e != nil; e = e.Next() {
+		cf = e.Value.(*CachedFile)
+		if cf.FileName == filename {
+			break
+		}
+	}
+
+	if e == nil {
+		content, err := ioutil.ReadFile(filename)
+		if err != nil {
+			return nil, err
+		}
+
+		cf = &CachedFile{
+			FileName: filename,
+			Lines:    bytes.Split(content, []byte{'\n'}),
+		}
+		fc.files.PushFront(cf)
+
+		if fc.files.Len() >= fc.maxLen {
+			fc.files.Remove(fc.files.Back())
+		}
+	} else {
+		fc.files.MoveToFront(e)
+	}
+
+	// because //line directives can be out-of-range. (#36683)
+	if line-1 >= len(cf.Lines) || line-1 < 0 {
+		return nil, nil
+	}
+
+	return cf.Lines[line-1], nil
+}
+
+// Print prints a disassembly of the file to w.
+// If filter is non-nil, the disassembly only includes functions with names matching filter.
+// If printCode is true, the disassembly includs corresponding source lines.
+// The disassembly only includes functions that overlap the range [start, end).
+func (d *Disasm) Print(w io.Writer, filter *regexp.Regexp, start, end uint64, printCode bool, gnuAsm bool) {
+	if start < d.textStart {
+		start = d.textStart
+	}
+	if end > d.textEnd {
+		end = d.textEnd
+	}
+	printed := false
+	bw := bufio.NewWriter(w)
+
+	var fc *FileCache
+	if printCode {
+		fc = NewFileCache(8)
+	}
+
+	tw := tabwriter.NewWriter(bw, 18, 8, 1, '\t', tabwriter.StripEscape)
+	for _, sym := range d.syms {
+		symStart := sym.Addr
+		symEnd := sym.Addr + uint64(sym.Size)
+		relocs := sym.Relocs
+		if sym.Code != 'T' && sym.Code != 't' ||
+			symStart < d.textStart ||
+			symEnd <= start || end <= symStart ||
+			filter != nil && !filter.MatchString(sym.Name) {
+			continue
+		}
+		if printed {
+			fmt.Fprintf(bw, "\n")
+		}
+		printed = true
+
+		file, _, _ := d.pcln.PCToLine(sym.Addr)
+		fmt.Fprintf(bw, "TEXT %s(SB) %s\n", sym.Name, file)
+
+		if symEnd > end {
+			symEnd = end
+		}
+		code := d.text[:end-d.textStart]
+
+		var lastFile string
+		var lastLine int
+
+		d.Decode(symStart, symEnd, relocs, gnuAsm, func(pc, size uint64, file string, line int, text string) {
+			i := pc - d.textStart
+
+			if printCode {
+				if file != lastFile || line != lastLine {
+					if srcLine, err := fc.Line(file, line); err == nil {
+						fmt.Fprintf(tw, "%s%s%s\n", []byte{tabwriter.Escape}, srcLine, []byte{tabwriter.Escape})
+					}
+
+					lastFile, lastLine = file, line
+				}
+
+				fmt.Fprintf(tw, "  %#x\t", pc)
+			} else {
+				fmt.Fprintf(tw, "  %s:%d\t%#x\t", base(file), line, pc)
+			}
+
+			if size%4 != 0 || d.goarch == "386" || d.goarch == "amd64" {
+				// Print instruction as bytes.
+				fmt.Fprintf(tw, "%x", code[i:i+size])
+			} else {
+				// Print instruction as 32-bit words.
+				for j := uint64(0); j < size; j += 4 {
+					if j > 0 {
+						fmt.Fprintf(tw, " ")
+					}
+					fmt.Fprintf(tw, "%08x", d.byteOrder.Uint32(code[i+j:]))
+				}
+			}
+			fmt.Fprintf(tw, "\t%s\t\n", text)
+		})
+		tw.Flush()
+	}
+	bw.Flush()
+}
+
+// Decode disassembles the text segment range [start, end), calling f for each instruction.
+func (d *Disasm) Decode(start, end uint64, relocs []Reloc, gnuAsm bool, f func(pc, size uint64, file string, line int, text string)) {
+	if start < d.textStart {
+		start = d.textStart
+	}
+	if end > d.textEnd {
+		end = d.textEnd
+	}
+	code := d.text[:end-d.textStart]
+	lookup := d.lookup
+	for pc := start; pc < end; {
+		i := pc - d.textStart
+		text, size := d.disasm(code[i:], pc, lookup, d.byteOrder, gnuAsm)
+		file, line, _ := d.pcln.PCToLine(pc)
+		sep := "\t"
+		for len(relocs) > 0 && relocs[0].Addr < i+uint64(size) {
+			text += sep + relocs[0].Stringer.String(pc-start)
+			sep = " "
+			relocs = relocs[1:]
+		}
+		f(pc, uint64(size), file, line, text)
+		pc += uint64(size)
+	}
+}
+
+type lookupFunc = func(addr uint64) (sym string, base uint64)
+type disasmFunc func(code []byte, pc uint64, lookup lookupFunc, ord binary.ByteOrder, _ bool) (text string, size int)
+
+func disasm_386(code []byte, pc uint64, lookup lookupFunc, _ binary.ByteOrder, gnuAsm bool) (string, int) {
+	return disasm_x86(code, pc, lookup, 32, gnuAsm)
+}
+
+func disasm_amd64(code []byte, pc uint64, lookup lookupFunc, _ binary.ByteOrder, gnuAsm bool) (string, int) {
+	return disasm_x86(code, pc, lookup, 64, gnuAsm)
+}
+
+func disasm_x86(code []byte, pc uint64, lookup lookupFunc, arch int, gnuAsm bool) (string, int) {
+	inst, err := x86asm.Decode(code, arch)
+	var text string
+	size := inst.Len
+	if err != nil || size == 0 || inst.Op == 0 {
+		size = 1
+		text = "?"
+	} else {
+		if gnuAsm {
+			text = fmt.Sprintf("%-36s // %s", x86asm.GoSyntax(inst, pc, lookup), x86asm.GNUSyntax(inst, pc, nil))
+		} else {
+			text = x86asm.GoSyntax(inst, pc, lookup)
+		}
+	}
+	return text, size
+}
+
+type textReader struct {
+	code []byte
+	pc   uint64
+}
+
+func (r textReader) ReadAt(data []byte, off int64) (n int, err error) {
+	if off < 0 || uint64(off) < r.pc {
+		return 0, io.EOF
+	}
+	d := uint64(off) - r.pc
+	if d >= uint64(len(r.code)) {
+		return 0, io.EOF
+	}
+	n = copy(data, r.code[d:])
+	if n < len(data) {
+		err = io.ErrUnexpectedEOF
+	}
+	return
+}
+
+func disasm_arm(code []byte, pc uint64, lookup lookupFunc, _ binary.ByteOrder, gnuAsm bool) (string, int) {
+	inst, err := armasm.Decode(code, armasm.ModeARM)
+	var text string
+	size := inst.Len
+	if err != nil || size == 0 || inst.Op == 0 {
+		size = 4
+		text = "?"
+	} else if gnuAsm {
+		text = fmt.Sprintf("%-36s // %s", armasm.GoSyntax(inst, pc, lookup, textReader{code, pc}), armasm.GNUSyntax(inst))
+	} else {
+		text = armasm.GoSyntax(inst, pc, lookup, textReader{code, pc})
+	}
+	return text, size
+}
+
+func disasm_arm64(code []byte, pc uint64, lookup lookupFunc, byteOrder binary.ByteOrder, gnuAsm bool) (string, int) {
+	inst, err := arm64asm.Decode(code)
+	var text string
+	if err != nil || inst.Op == 0 {
+		text = "?"
+	} else if gnuAsm {
+		text = fmt.Sprintf("%-36s // %s", arm64asm.GoSyntax(inst, pc, lookup, textReader{code, pc}), arm64asm.GNUSyntax(inst))
+	} else {
+		text = arm64asm.GoSyntax(inst, pc, lookup, textReader{code, pc})
+	}
+	return text, 4
+}
+
+func disasm_ppc64(code []byte, pc uint64, lookup lookupFunc, byteOrder binary.ByteOrder, gnuAsm bool) (string, int) {
+	inst, err := ppc64asm.Decode(code, byteOrder)
+	var text string
+	size := inst.Len
+	if err != nil || size == 0 {
+		size = 4
+		text = "?"
+	} else {
+		if gnuAsm {
+			text = fmt.Sprintf("%-36s // %s", ppc64asm.GoSyntax(inst, pc, lookup), ppc64asm.GNUSyntax(inst, pc))
+		} else {
+			text = ppc64asm.GoSyntax(inst, pc, lookup)
+		}
+	}
+	return text, size
+}
+
+var disasms = map[string]disasmFunc{
+	"386":     disasm_386,
+	"amd64":   disasm_amd64,
+	"arm":     disasm_arm,
+	"arm64":   disasm_arm64,
+	"ppc64":   disasm_ppc64,
+	"ppc64le": disasm_ppc64,
+}
+
+var byteOrders = map[string]binary.ByteOrder{
+	"386":     binary.LittleEndian,
+	"amd64":   binary.LittleEndian,
+	"arm":     binary.LittleEndian,
+	"arm64":   binary.LittleEndian,
+	"ppc64":   binary.BigEndian,
+	"ppc64le": binary.LittleEndian,
+	"s390x":   binary.BigEndian,
+}
+
+type Liner interface {
+	// Given a pc, returns the corresponding file, line, and function data.
+	// If unknown, returns "",0,nil.
+	PCToLine(uint64) (string, int, *gosym.Func)
+}