1 files changed, 606 insertions, 0 deletions
diff --git a/vendor/github.com/google/gops/internal/obj/objfile.go b/vendor/github.com/google/gops/internal/obj/objfile.go
new file mode 100644
index 00000000..8a897f09
--- /dev/null
+++ b/vendor/github.com/google/gops/internal/obj/objfile.go
@@ -0,0 +1,606 @@
+// Copyright 2013 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.
+
+// Writing of Go object files.
+//
+// Originally, Go object files were Plan 9 object files, but no longer.
+// Now they are more like standard object files, in that each symbol is defined
+// by an associated memory image (bytes) and a list of relocations to apply
+// during linking. We do not (yet?) use a standard file format, however.
+// For now, the format is chosen to be as simple as possible to read and write.
+// It may change for reasons of efficiency, or we may even switch to a
+// standard file format if there are compelling benefits to doing so.
+// See golang.org/s/go13linker for more background.
+//
+// The file format is:
+//
+//	- magic header: "\x00\x00go17ld"
+//	- byte 1 - version number
+//	- sequence of strings giving dependencies (imported packages)
+//	- empty string (marks end of sequence)
+//	- sequence of symbol references used by the defined symbols
+//	- byte 0xff (marks end of sequence)
+//	- sequence of integer lengths:
+//		- total data length
+//		- total number of relocations
+//		- total number of pcdata
+//		- total number of automatics
+//		- total number of funcdata
+//		- total number of files
+//	- data, the content of the defined symbols
+//	- sequence of defined symbols
+//	- byte 0xff (marks end of sequence)
+//	- magic footer: "\xff\xffgo17ld"
+//
+// All integers are stored in a zigzag varint format.
+// See golang.org/s/go12symtab for a definition.
+//
+// Data blocks and strings are both stored as an integer
+// followed by that many bytes.
+//
+// A symbol reference is a string name followed by a version.
+//
+// A symbol points to other symbols using an index into the symbol
+// reference sequence. Index 0 corresponds to a nil LSym* pointer.
+// In the symbol layout described below "symref index" stands for this
+// index.
+//
+// Each symbol is laid out as the following fields (taken from LSym*):
+//
+//	- byte 0xfe (sanity check for synchronization)
+//	- type [int]
+//	- name & version [symref index]
+//	- flags [int]
+//		1<<0 dupok
+//		1<<1 local
+//		1<<2 add to typelink table
+//	- size [int]
+//	- gotype [symref index]
+//	- p [data block]
+//	- nr [int]
+//	- r [nr relocations, sorted by off]
+//
+// If type == STEXT, there are a few more fields:
+//
+//	- args [int]
+//	- locals [int]
+//	- nosplit [int]
+//	- flags [int]
+//		1<<0 leaf
+//		1<<1 C function
+//		1<<2 function may call reflect.Type.Method
+//	- nlocal [int]
+//	- local [nlocal automatics]
+//	- pcln [pcln table]
+//
+// Each relocation has the encoding:
+//
+//	- off [int]
+//	- siz [int]
+//	- type [int]
+//	- add [int]
+//	- sym [symref index]
+//
+// Each local has the encoding:
+//
+//	- asym [symref index]
+//	- offset [int]
+//	- type [int]
+//	- gotype [symref index]
+//
+// The pcln table has the encoding:
+//
+//	- pcsp [data block]
+//	- pcfile [data block]
+//	- pcline [data block]
+//	- npcdata [int]
+//	- pcdata [npcdata data blocks]
+//	- nfuncdata [int]
+//	- funcdata [nfuncdata symref index]
+//	- funcdatasym [nfuncdata ints]
+//	- nfile [int]
+//	- file [nfile symref index]
+//
+// The file layout and meaning of type integers are architecture-independent.
+//
+// TODO(rsc): The file format is good for a first pass but needs work.
+//	- There are SymID in the object file that should really just be strings.
+
+package obj
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"path/filepath"
+	"sort"
+
+	"github.com/google/gops/internal/dwarf"
+	"github.com/google/gops/internal/sys"
+)
+
+// The Go and C compilers, and the assembler, call writeobj to write
+// out a Go object file. The linker does not call this; the linker
+// does not write out object files.
+func Writeobjdirect(ctxt *Link, b *bufio.Writer) {
+	Flushplist(ctxt)
+	WriteObjFile(ctxt, b)
+}
+
+// objWriter writes Go object files.
+type objWriter struct {
+	wr   *bufio.Writer
+	ctxt *Link
+	// Temporary buffer for zigzag int writing.
+	varintbuf [10]uint8
+
+	// Provide the the index of a symbol reference by symbol name.
+	// One map for versioned symbols and one for unversioned symbols.
+	// Used for deduplicating the symbol reference list.
+	refIdx  map[string]int
+	vrefIdx map[string]int
+
+	// Number of objects written of each type.
+	nRefs     int
+	nData     int
+	nReloc    int
+	nPcdata   int
+	nAutom    int
+	nFuncdata int
+	nFile     int
+}
+
+func (w *objWriter) addLengths(s *LSym) {
+	w.nData += len(s.P)
+	w.nReloc += len(s.R)
+
+	if s.Type != STEXT {
+		return
+	}
+
+	pc := s.Pcln
+
+	data := 0
+	data += len(pc.Pcsp.P)
+	data += len(pc.Pcfile.P)
+	data += len(pc.Pcline.P)
+	for i := 0; i < len(pc.Pcdata); i++ {
+		data += len(pc.Pcdata[i].P)
+	}
+
+	w.nData += data
+	w.nPcdata += len(pc.Pcdata)
+
+	autom := 0
+	for a := s.Autom; a != nil; a = a.Link {
+		autom++
+	}
+	w.nAutom += autom
+	w.nFuncdata += len(pc.Funcdataoff)
+	w.nFile += len(pc.File)
+}
+
+func (w *objWriter) writeLengths() {
+	w.writeInt(int64(w.nData))
+	w.writeInt(int64(w.nReloc))
+	w.writeInt(int64(w.nPcdata))
+	w.writeInt(int64(w.nAutom))
+	w.writeInt(int64(w.nFuncdata))
+	w.writeInt(int64(w.nFile))
+}
+
+func newObjWriter(ctxt *Link, b *bufio.Writer) *objWriter {
+	return &objWriter{
+		ctxt:    ctxt,
+		wr:      b,
+		vrefIdx: make(map[string]int),
+		refIdx:  make(map[string]int),
+	}
+}
+
+func WriteObjFile(ctxt *Link, b *bufio.Writer) {
+	w := newObjWriter(ctxt, b)
+
+	// Magic header
+	w.wr.WriteString("\x00\x00go17ld")
+
+	// Version
+	w.wr.WriteByte(1)
+
+	// Autolib
+	for _, pkg := range ctxt.Imports {
+		w.writeString(pkg)
+	}
+	w.writeString("")
+
+	// Symbol references
+	for _, s := range ctxt.Text {
+		w.writeRefs(s)
+		w.addLengths(s)
+	}
+	for _, s := range ctxt.Data {
+		w.writeRefs(s)
+		w.addLengths(s)
+	}
+	// End symbol references
+	w.wr.WriteByte(0xff)
+
+	// Lengths
+	w.writeLengths()
+
+	// Data block
+	for _, s := range ctxt.Text {
+		w.wr.Write(s.P)
+		pc := s.Pcln
+		w.wr.Write(pc.Pcsp.P)
+		w.wr.Write(pc.Pcfile.P)
+		w.wr.Write(pc.Pcline.P)
+		for i := 0; i < len(pc.Pcdata); i++ {
+			w.wr.Write(pc.Pcdata[i].P)
+		}
+	}
+	for _, s := range ctxt.Data {
+		w.wr.Write(s.P)
+	}
+
+	// Symbols
+	for _, s := range ctxt.Text {
+		w.writeSym(s)
+	}
+	for _, s := range ctxt.Data {
+		w.writeSym(s)
+	}
+
+	// Magic footer
+	w.wr.WriteString("\xff\xffgo17ld")
+}
+
+// Symbols are prefixed so their content doesn't get confused with the magic footer.
+const symPrefix = 0xfe
+
+func (w *objWriter) writeRef(s *LSym, isPath bool) {
+	if s == nil || s.RefIdx != 0 {
+		return
+	}
+	var m map[string]int
+	switch s.Version {
+	case 0:
+		m = w.refIdx
+	case 1:
+		m = w.vrefIdx
+	default:
+		log.Fatalf("%s: invalid version number %d", s.Name, s.Version)
+	}
+
+	idx := m[s.Name]
+	if idx != 0 {
+		s.RefIdx = idx
+		return
+	}
+	w.wr.WriteByte(symPrefix)
+	if isPath {
+		w.writeString(filepath.ToSlash(s.Name))
+	} else {
+		w.writeString(s.Name)
+	}
+	w.writeInt(int64(s.Version))
+	w.nRefs++
+	s.RefIdx = w.nRefs
+	m[s.Name] = w.nRefs
+}
+
+func (w *objWriter) writeRefs(s *LSym) {
+	w.writeRef(s, false)
+	w.writeRef(s.Gotype, false)
+	for i := range s.R {
+		w.writeRef(s.R[i].Sym, false)
+	}
+
+	if s.Type == STEXT {
+		for a := s.Autom; a != nil; a = a.Link {
+			w.writeRef(a.Asym, false)
+			w.writeRef(a.Gotype, false)
+		}
+		pc := s.Pcln
+		for _, d := range pc.Funcdata {
+			w.writeRef(d, false)
+		}
+		for _, f := range pc.File {
+			w.writeRef(f, true)
+		}
+	}
+}
+
+func (w *objWriter) writeSymDebug(s *LSym) {
+	ctxt := w.ctxt
+	fmt.Fprintf(ctxt.Bso, "%s ", s.Name)
+	if s.Version != 0 {
+		fmt.Fprintf(ctxt.Bso, "v=%d ", s.Version)
+	}
+	if s.Type != 0 {
+		fmt.Fprintf(ctxt.Bso, "t=%d ", s.Type)
+	}
+	if s.DuplicateOK() {
+		fmt.Fprintf(ctxt.Bso, "dupok ")
+	}
+	if s.CFunc() {
+		fmt.Fprintf(ctxt.Bso, "cfunc ")
+	}
+	if s.NoSplit() {
+		fmt.Fprintf(ctxt.Bso, "nosplit ")
+	}
+	fmt.Fprintf(ctxt.Bso, "size=%d", s.Size)
+	if s.Type == STEXT {
+		fmt.Fprintf(ctxt.Bso, " args=%#x locals=%#x", uint64(s.Args), uint64(s.Locals))
+		if s.Leaf() {
+			fmt.Fprintf(ctxt.Bso, " leaf")
+		}
+	}
+
+	fmt.Fprintf(ctxt.Bso, "\n")
+	for p := s.Text; p != nil; p = p.Link {
+		fmt.Fprintf(ctxt.Bso, "\t%#04x %v\n", uint(int(p.Pc)), p)
+	}
+	var c int
+	var j int
+	for i := 0; i < len(s.P); {
+		fmt.Fprintf(ctxt.Bso, "\t%#04x", uint(i))
+		for j = i; j < i+16 && j < len(s.P); j++ {
+			fmt.Fprintf(ctxt.Bso, " %02x", s.P[j])
+		}
+		for ; j < i+16; j++ {
+			fmt.Fprintf(ctxt.Bso, "   ")
+		}
+		fmt.Fprintf(ctxt.Bso, "  ")
+		for j = i; j < i+16 && j < len(s.P); j++ {
+			c = int(s.P[j])
+			if ' ' <= c && c <= 0x7e {
+				fmt.Fprintf(ctxt.Bso, "%c", c)
+			} else {
+				fmt.Fprintf(ctxt.Bso, ".")
+			}
+		}
+
+		fmt.Fprintf(ctxt.Bso, "\n")
+		i += 16
+	}
+
+	sort.Sort(relocByOff(s.R)) // generate stable output
+	for _, r := range s.R {
+		name := ""
+		if r.Sym != nil {
+			name = r.Sym.Name
+		} else if r.Type == R_TLS_LE {
+			name = "TLS"
+		}
+		if ctxt.Arch.InFamily(sys.ARM, sys.PPC64) {
+			fmt.Fprintf(ctxt.Bso, "\trel %d+%d t=%d %s+%x\n", int(r.Off), r.Siz, r.Type, name, uint64(r.Add))
+		} else {
+			fmt.Fprintf(ctxt.Bso, "\trel %d+%d t=%d %s+%d\n", int(r.Off), r.Siz, r.Type, name, r.Add)
+		}
+	}
+}
+
+func (w *objWriter) writeSym(s *LSym) {
+	ctxt := w.ctxt
+	if ctxt.Debugasm != 0 {
+		w.writeSymDebug(s)
+	}
+
+	w.wr.WriteByte(symPrefix)
+	w.writeInt(int64(s.Type))
+	w.writeRefIndex(s)
+	flags := int64(0)
+	if s.DuplicateOK() {
+		flags |= 1
+	}
+	if s.Local() {
+		flags |= 1 << 1
+	}
+	if s.MakeTypelink() {
+		flags |= 1 << 2
+	}
+	w.writeInt(flags)
+	w.writeInt(s.Size)
+	w.writeRefIndex(s.Gotype)
+	w.writeInt(int64(len(s.P)))
+
+	w.writeInt(int64(len(s.R)))
+	var r *Reloc
+	for i := 0; i < len(s.R); i++ {
+		r = &s.R[i]
+		w.writeInt(int64(r.Off))
+		w.writeInt(int64(r.Siz))
+		w.writeInt(int64(r.Type))
+		w.writeInt(r.Add)
+		w.writeRefIndex(r.Sym)
+	}
+
+	if s.Type != STEXT {
+		return
+	}
+
+	w.writeInt(int64(s.Args))
+	w.writeInt(int64(s.Locals))
+	if s.NoSplit() {
+		w.writeInt(1)
+	} else {
+		w.writeInt(0)
+	}
+	flags = int64(0)
+	if s.Leaf() {
+		flags |= 1
+	}
+	if s.CFunc() {
+		flags |= 1 << 1
+	}
+	if s.ReflectMethod() {
+		flags |= 1 << 2
+	}
+	w.writeInt(flags)
+	n := 0
+	for a := s.Autom; a != nil; a = a.Link {
+		n++
+	}
+	w.writeInt(int64(n))
+	for a := s.Autom; a != nil; a = a.Link {
+		w.writeRefIndex(a.Asym)
+		w.writeInt(int64(a.Aoffset))
+		if a.Name == NAME_AUTO {
+			w.writeInt(A_AUTO)
+		} else if a.Name == NAME_PARAM {
+			w.writeInt(A_PARAM)
+		} else {
+			log.Fatalf("%s: invalid local variable type %d", s.Name, a.Name)
+		}
+		w.writeRefIndex(a.Gotype)
+	}
+
+	pc := s.Pcln
+	w.writeInt(int64(len(pc.Pcsp.P)))
+	w.writeInt(int64(len(pc.Pcfile.P)))
+	w.writeInt(int64(len(pc.Pcline.P)))
+	w.writeInt(int64(len(pc.Pcdata)))
+	for i := 0; i < len(pc.Pcdata); i++ {
+		w.writeInt(int64(len(pc.Pcdata[i].P)))
+	}
+	w.writeInt(int64(len(pc.Funcdataoff)))
+	for i := 0; i < len(pc.Funcdataoff); i++ {
+		w.writeRefIndex(pc.Funcdata[i])
+	}
+	for i := 0; i < len(pc.Funcdataoff); i++ {
+		w.writeInt(pc.Funcdataoff[i])
+	}
+	w.writeInt(int64(len(pc.File)))
+	for _, f := range pc.File {
+		w.writeRefIndex(f)
+	}
+}
+
+func (w *objWriter) writeInt(sval int64) {
+	var v uint64
+	uv := (uint64(sval) << 1) ^ uint64(sval>>63)
+	p := w.varintbuf[:]
+	for v = uv; v >= 0x80; v >>= 7 {
+		p[0] = uint8(v | 0x80)
+		p = p[1:]
+	}
+	p[0] = uint8(v)
+	p = p[1:]
+	w.wr.Write(w.varintbuf[:len(w.varintbuf)-len(p)])
+}
+
+func (w *objWriter) writeString(s string) {
+	w.writeInt(int64(len(s)))
+	w.wr.WriteString(s)
+}
+
+func (w *objWriter) writeRefIndex(s *LSym) {
+	if s == nil {
+		w.writeInt(0)
+		return
+	}
+	if s.RefIdx == 0 {
+		log.Fatalln("writing an unreferenced symbol", s.Name)
+	}
+	w.writeInt(int64(s.RefIdx))
+}
+
+// relocByOff sorts relocations by their offsets.
+type relocByOff []Reloc
+
+func (x relocByOff) Len() int           { return len(x) }
+func (x relocByOff) Less(i, j int) bool { return x[i].Off < x[j].Off }
+func (x relocByOff) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
+
+// implement dwarf.Context
+type dwCtxt struct{ *Link }
+
+func (c dwCtxt) PtrSize() int {
+	return c.Arch.PtrSize
+}
+func (c dwCtxt) AddInt(s dwarf.Sym, size int, i int64) {
+	ls := s.(*LSym)
+	ls.WriteInt(c.Link, ls.Size, size, i)
+}
+func (c dwCtxt) AddBytes(s dwarf.Sym, b []byte) {
+	ls := s.(*LSym)
+	ls.WriteBytes(c.Link, ls.Size, b)
+}
+func (c dwCtxt) AddString(s dwarf.Sym, v string) {
+	ls := s.(*LSym)
+	ls.WriteString(c.Link, ls.Size, len(v), v)
+	ls.WriteInt(c.Link, ls.Size, 1, 0)
+}
+func (c dwCtxt) SymValue(s dwarf.Sym) int64 {
+	return 0
+}
+func (c dwCtxt) AddAddress(s dwarf.Sym, data interface{}, value int64) {
+	rsym := data.(*LSym)
+	ls := s.(*LSym)
+	size := c.PtrSize()
+	ls.WriteAddr(c.Link, ls.Size, size, rsym, value)
+}
+func (c dwCtxt) AddSectionOffset(s dwarf.Sym, size int, t interface{}, ofs int64) {
+	ls := s.(*LSym)
+	rsym := t.(*LSym)
+	ls.WriteAddr(c.Link, ls.Size, size, rsym, ofs)
+	r := &ls.R[len(ls.R)-1]
+	r.Type = R_DWARFREF
+}
+
+func gendwarf(ctxt *Link, text []*LSym) []*LSym {
+	dctxt := dwCtxt{ctxt}
+	var dw []*LSym
+
+	for _, s := range text {
+		dsym := Linklookup(ctxt, dwarf.InfoPrefix+s.Name, int(s.Version))
+		if dsym.Size != 0 {
+			continue
+		}
+		dw = append(dw, dsym)
+		dsym.Type = SDWARFINFO
+		dsym.Set(AttrDuplicateOK, s.DuplicateOK())
+		var vars dwarf.Var
+		var abbrev int
+		var offs int32
+		for a := s.Autom; a != nil; a = a.Link {
+			switch a.Name {
+			case NAME_AUTO:
+				abbrev = dwarf.DW_ABRV_AUTO
+				offs = a.Aoffset
+				if ctxt.FixedFrameSize() == 0 {
+					offs -= int32(ctxt.Arch.PtrSize)
+				}
+				if Framepointer_enabled(GOOS, GOARCH) {
+					offs -= int32(ctxt.Arch.PtrSize)
+				}
+
+			case NAME_PARAM:
+				abbrev = dwarf.DW_ABRV_PARAM
+				offs = a.Aoffset + int32(ctxt.FixedFrameSize())
+
+			default:
+				continue
+			}
+			typename := dwarf.InfoPrefix + a.Gotype.Name[len("type."):]
+			dwvar := &dwarf.Var{
+				Name:   a.Asym.Name,
+				Abbrev: abbrev,
+				Offset: int32(offs),
+				Type:   Linklookup(ctxt, typename, 0),
+			}
+			dws := &vars.Link
+			for ; *dws != nil; dws = &(*dws).Link {
+				if offs <= (*dws).Offset {
+					break
+				}
+			}
+			dwvar.Link = *dws
+			*dws = dwvar
+		}
+		dwarf.PutFunc(dctxt, dsym, s.Name, s.Version == 0, s, s.Size, vars.Link)
+	}
+	return dw
+}