17 files changed, 1565 insertions, 0 deletions
diff --git a/src/cmd/internal/objabi/autotype.go b/src/cmd/internal/objabi/autotype.go
new file mode 100644
index 0000000..f9d17a3
--- /dev/null
+++ b/src/cmd/internal/objabi/autotype.go
@@ -0,0 +1,38 @@
+// Derived from Inferno utils/6l/l.h and related files.
+// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/l.h
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors. All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package objabi
+
+// Auto.name
+const (
+	A_AUTO = 1 + iota
+	A_PARAM
+	A_DELETED_AUTO
+)
diff --git a/src/cmd/internal/objabi/flag.go b/src/cmd/internal/objabi/flag.go
new file mode 100644
index 0000000..f75c054
--- /dev/null
+++ b/src/cmd/internal/objabi/flag.go
@@ -0,0 +1,368 @@
+// Copyright 2015 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 objabi
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"internal/buildcfg"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"reflect"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+func Flagcount(name, usage string, val *int) {
+	flag.Var((*count)(val), name, usage)
+}
+
+func Flagfn1(name, usage string, f func(string)) {
+	flag.Var(fn1(f), name, usage)
+}
+
+func Flagprint(w io.Writer) {
+	flag.CommandLine.SetOutput(w)
+	flag.PrintDefaults()
+}
+
+func Flagparse(usage func()) {
+	flag.Usage = usage
+	os.Args = expandArgs(os.Args)
+	flag.Parse()
+}
+
+// expandArgs expands "response files" arguments in the provided slice.
+//
+// A "response file" argument starts with '@' and the rest of that
+// argument is a filename with CR-or-CRLF-separated arguments. Each
+// argument in the named files can also contain response file
+// arguments. See Issue 18468.
+//
+// The returned slice 'out' aliases 'in' iff the input did not contain
+// any response file arguments.
+//
+// TODO: handle relative paths of recursive expansions in different directories?
+// Is there a spec for this? Are relative paths allowed?
+func expandArgs(in []string) (out []string) {
+	// out is nil until we see a "@" argument.
+	for i, s := range in {
+		if strings.HasPrefix(s, "@") {
+			if out == nil {
+				out = make([]string, 0, len(in)*2)
+				out = append(out, in[:i]...)
+			}
+			slurp, err := ioutil.ReadFile(s[1:])
+			if err != nil {
+				log.Fatal(err)
+			}
+			args := strings.Split(strings.TrimSpace(strings.Replace(string(slurp), "\r", "", -1)), "\n")
+			for i, arg := range args {
+				args[i] = DecodeArg(arg)
+			}
+			out = append(out, expandArgs(args)...)
+		} else if out != nil {
+			out = append(out, s)
+		}
+	}
+	if out == nil {
+		return in
+	}
+	return
+}
+
+func AddVersionFlag() {
+	flag.Var(versionFlag{}, "V", "print version and exit")
+}
+
+var buildID string // filled in by linker
+
+type versionFlag struct{}
+
+func (versionFlag) IsBoolFlag() bool { return true }
+func (versionFlag) Get() interface{} { return nil }
+func (versionFlag) String() string   { return "" }
+func (versionFlag) Set(s string) error {
+	name := os.Args[0]
+	name = name[strings.LastIndex(name, `/`)+1:]
+	name = name[strings.LastIndex(name, `\`)+1:]
+	name = strings.TrimSuffix(name, ".exe")
+
+	p := ""
+
+	if s == "goexperiment" {
+		// test/run.go uses this to discover the full set of
+		// experiment tags. Report everything.
+		p = " X:" + strings.Join(buildcfg.AllExperiments(), ",")
+	} else {
+		// If the enabled experiments differ from the defaults,
+		// include that difference.
+		if goexperiment := buildcfg.GOEXPERIMENT(); goexperiment != "" {
+			p = " X:" + goexperiment
+		}
+	}
+
+	// The go command invokes -V=full to get a unique identifier
+	// for this tool. It is assumed that the release version is sufficient
+	// for releases, but during development we include the full
+	// build ID of the binary, so that if the compiler is changed and
+	// rebuilt, we notice and rebuild all packages.
+	if s == "full" {
+		if strings.HasPrefix(buildcfg.Version, "devel") {
+			p += " buildID=" + buildID
+		}
+	}
+
+	fmt.Printf("%s version %s%s\n", name, buildcfg.Version, p)
+	os.Exit(0)
+	return nil
+}
+
+// count is a flag.Value that is like a flag.Bool and a flag.Int.
+// If used as -name, it increments the count, but -name=x sets the count.
+// Used for verbose flag -v.
+type count int
+
+func (c *count) String() string {
+	return fmt.Sprint(int(*c))
+}
+
+func (c *count) Set(s string) error {
+	switch s {
+	case "true":
+		*c++
+	case "false":
+		*c = 0
+	default:
+		n, err := strconv.Atoi(s)
+		if err != nil {
+			return fmt.Errorf("invalid count %q", s)
+		}
+		*c = count(n)
+	}
+	return nil
+}
+
+func (c *count) Get() interface{} {
+	return int(*c)
+}
+
+func (c *count) IsBoolFlag() bool {
+	return true
+}
+
+func (c *count) IsCountFlag() bool {
+	return true
+}
+
+type fn1 func(string)
+
+func (f fn1) Set(s string) error {
+	f(s)
+	return nil
+}
+
+func (f fn1) String() string { return "" }
+
+// DecodeArg decodes an argument.
+//
+// This function is public for testing with the parallel encoder.
+func DecodeArg(arg string) string {
+	// If no encoding, fastpath out.
+	if !strings.ContainsAny(arg, "\\\n") {
+		return arg
+	}
+
+	// We can't use strings.Builder as this must work at bootstrap.
+	var b bytes.Buffer
+	var wasBS bool
+	for _, r := range arg {
+		if wasBS {
+			switch r {
+			case '\\':
+				b.WriteByte('\\')
+			case 'n':
+				b.WriteByte('\n')
+			default:
+				// This shouldn't happen. The only backslashes that reach here
+				// should encode '\n' and '\\' exclusively.
+				panic("badly formatted input")
+			}
+		} else if r == '\\' {
+			wasBS = true
+			continue
+		} else {
+			b.WriteRune(r)
+		}
+		wasBS = false
+	}
+	return b.String()
+}
+
+type debugField struct {
+	name string
+	help string
+	val  interface{} // *int or *string
+}
+
+type DebugFlag struct {
+	tab map[string]debugField
+	any *bool
+
+	debugSSA DebugSSA
+}
+
+// A DebugSSA function is called to set a -d ssa/... option.
+// If nil, those options are reported as invalid options.
+// If DebugSSA returns a non-empty string, that text is reported as a compiler error.
+// If phase is "help", it should print usage information and terminate the process.
+type DebugSSA func(phase, flag string, val int, valString string) string
+
+// NewDebugFlag constructs a DebugFlag for the fields of debug, which
+// must be a pointer to a struct.
+//
+// Each field of *debug is a different value, named for the lower-case of the field name.
+// Each field must be an int or string and must have a `help` struct tag.
+// There may be an "Any bool" field, which will be set if any debug flags are set.
+//
+// The returned flag takes a comma-separated list of settings.
+// Each setting is name=value; for ints, name is short for name=1.
+//
+// If debugSSA is non-nil, any debug flags of the form ssa/... will be
+// passed to debugSSA for processing.
+func NewDebugFlag(debug interface{}, debugSSA DebugSSA) *DebugFlag {
+	flag := &DebugFlag{
+		tab:      make(map[string]debugField),
+		debugSSA: debugSSA,
+	}
+
+	v := reflect.ValueOf(debug).Elem()
+	t := v.Type()
+	for i := 0; i < t.NumField(); i++ {
+		f := t.Field(i)
+		ptr := v.Field(i).Addr().Interface()
+		if f.Name == "Any" {
+			switch ptr := ptr.(type) {
+			default:
+				panic("debug.Any must have type bool")
+			case *bool:
+				flag.any = ptr
+			}
+			continue
+		}
+		name := strings.ToLower(f.Name)
+		help := f.Tag.Get("help")
+		if help == "" {
+			panic(fmt.Sprintf("debug.%s is missing help text", f.Name))
+		}
+		switch ptr.(type) {
+		default:
+			panic(fmt.Sprintf("debug.%s has invalid type %v (must be int or string)", f.Name, f.Type))
+		case *int, *string:
+			// ok
+		}
+		flag.tab[name] = debugField{name, help, ptr}
+	}
+
+	return flag
+}
+
+func (f *DebugFlag) Set(debugstr string) error {
+	if debugstr == "" {
+		return nil
+	}
+	if f.any != nil {
+		*f.any = true
+	}
+	for _, name := range strings.Split(debugstr, ",") {
+		if name == "" {
+			continue
+		}
+		// display help about the debug option itself and quit
+		if name == "help" {
+			fmt.Print(debugHelpHeader)
+			maxLen, names := 0, []string{}
+			if f.debugSSA != nil {
+				maxLen = len("ssa/help")
+			}
+			for name := range f.tab {
+				if len(name) > maxLen {
+					maxLen = len(name)
+				}
+				names = append(names, name)
+			}
+			sort.Strings(names)
+			// Indent multi-line help messages.
+			nl := fmt.Sprintf("\n\t%-*s\t", maxLen, "")
+			for _, name := range names {
+				help := f.tab[name].help
+				fmt.Printf("\t%-*s\t%s\n", maxLen, name, strings.Replace(help, "\n", nl, -1))
+			}
+			if f.debugSSA != nil {
+				// ssa options have their own help
+				fmt.Printf("\t%-*s\t%s\n", maxLen, "ssa/help", "print help about SSA debugging")
+			}
+			os.Exit(0)
+		}
+
+		val, valstring, haveInt := 1, "", true
+		if i := strings.IndexAny(name, "=:"); i >= 0 {
+			var err error
+			name, valstring = name[:i], name[i+1:]
+			val, err = strconv.Atoi(valstring)
+			if err != nil {
+				val, haveInt = 1, false
+			}
+		}
+
+		if t, ok := f.tab[name]; ok {
+			switch vp := t.val.(type) {
+			case nil:
+				// Ignore
+			case *string:
+				*vp = valstring
+			case *int:
+				if !haveInt {
+					log.Fatalf("invalid debug value %v", name)
+				}
+				*vp = val
+			default:
+				panic("bad debugtab type")
+			}
+		} else if f.debugSSA != nil && strings.HasPrefix(name, "ssa/") {
+			// expect form ssa/phase/flag
+			// e.g. -d=ssa/generic_cse/time
+			// _ in phase name also matches space
+			phase := name[4:]
+			flag := "debug" // default flag is debug
+			if i := strings.Index(phase, "/"); i >= 0 {
+				flag = phase[i+1:]
+				phase = phase[:i]
+			}
+			err := f.debugSSA(phase, flag, val, valstring)
+			if err != "" {
+				log.Fatalf(err)
+			}
+		} else {
+			return fmt.Errorf("unknown debug key %s\n", name)
+		}
+	}
+
+	return nil
+}
+
+const debugHelpHeader = `usage: -d arg[,arg]* and arg is <key>[=<value>]
+
+<key> is one of:
+
+`
+
+func (f *DebugFlag) String() string {
+	return ""
+}
diff --git a/src/cmd/internal/objabi/flag_test.go b/src/cmd/internal/objabi/flag_test.go
new file mode 100644
index 0000000..935b9c2
--- /dev/null
+++ b/src/cmd/internal/objabi/flag_test.go
@@ -0,0 +1,26 @@
+// Copyright 2020 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 objabi
+
+import "testing"
+
+func TestDecodeArg(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		arg, want string
+	}{
+		{"", ""},
+		{"hello", "hello"},
+		{"hello\\n", "hello\n"},
+		{"hello\\nthere", "hello\nthere"},
+		{"hello\\\\there", "hello\\there"},
+		{"\\\\\\n", "\\\n"},
+	}
+	for _, test := range tests {
+		if got := DecodeArg(test.arg); got != test.want {
+			t.Errorf("decodoeArg(%q) = %q, want %q", test.arg, got, test.want)
+		}
+	}
+}
diff --git a/src/cmd/internal/objabi/funcdata.go b/src/cmd/internal/objabi/funcdata.go
new file mode 100644
index 0000000..05a1d49
--- /dev/null
+++ b/src/cmd/internal/objabi/funcdata.go
@@ -0,0 +1,51 @@
+// 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.
+
+package objabi
+
+// This file defines the IDs for PCDATA and FUNCDATA instructions
+// in Go binaries.
+//
+// These must agree with ../../../runtime/funcdata.h and
+// ../../../runtime/symtab.go.
+
+const (
+	PCDATA_UnsafePoint   = 0
+	PCDATA_StackMapIndex = 1
+	PCDATA_InlTreeIndex  = 2
+	PCDATA_ArgLiveIndex  = 3
+
+	FUNCDATA_ArgsPointerMaps    = 0
+	FUNCDATA_LocalsPointerMaps  = 1
+	FUNCDATA_StackObjects       = 2
+	FUNCDATA_InlTree            = 3
+	FUNCDATA_OpenCodedDeferInfo = 4
+	FUNCDATA_ArgInfo            = 5
+	FUNCDATA_ArgLiveInfo        = 6
+	FUNCDATA_WrapInfo           = 7
+
+	// ArgsSizeUnknown is set in Func.argsize to mark all functions
+	// whose argument size is unknown (C vararg functions, and
+	// assembly code without an explicit specification).
+	// This value is generated by the compiler, assembler, or linker.
+	ArgsSizeUnknown = -0x80000000
+)
+
+// Special PCDATA values.
+const (
+	// PCDATA_UnsafePoint values.
+	PCDATA_UnsafePointSafe   = -1 // Safe for async preemption
+	PCDATA_UnsafePointUnsafe = -2 // Unsafe for async preemption
+
+	// PCDATA_Restart1(2) apply on a sequence of instructions, within
+	// which if an async preemption happens, we should back off the PC
+	// to the start of the sequence when resuming.
+	// We need two so we can distinguish the start/end of the sequence
+	// in case that two sequences are next to each other.
+	PCDATA_Restart1 = -3
+	PCDATA_Restart2 = -4
+
+	// Like PCDATA_Restart1, but back to function entry if async preempted.
+	PCDATA_RestartAtEntry = -5
+)
diff --git a/src/cmd/internal/objabi/funcid.go b/src/cmd/internal/objabi/funcid.go
new file mode 100644
index 0000000..084fcdf
--- /dev/null
+++ b/src/cmd/internal/objabi/funcid.go
@@ -0,0 +1,91 @@
+// Copyright 2018 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 objabi
+
+import "strings"
+
+// A FuncFlag records bits about a function, passed to the runtime.
+type FuncFlag uint8
+
+// Note: This list must match the list in runtime/symtab.go.
+const (
+	FuncFlag_TOPFRAME = 1 << iota
+	FuncFlag_SPWRITE
+	FuncFlag_ASM
+)
+
+// A FuncID identifies particular functions that need to be treated
+// specially by the runtime.
+// Note that in some situations involving plugins, there may be multiple
+// copies of a particular special runtime function.
+type FuncID uint8
+
+// Note: this list must match the list in runtime/symtab.go.
+const (
+	FuncID_normal FuncID = iota // not a special function
+	FuncID_abort
+	FuncID_asmcgocall
+	FuncID_asyncPreempt
+	FuncID_cgocallback
+	FuncID_debugCallV2
+	FuncID_gcBgMarkWorker
+	FuncID_goexit
+	FuncID_gogo
+	FuncID_gopanic
+	FuncID_handleAsyncEvent
+	FuncID_mcall
+	FuncID_morestack
+	FuncID_mstart
+	FuncID_panicwrap
+	FuncID_rt0_go
+	FuncID_runfinq
+	FuncID_runtime_main
+	FuncID_sigpanic
+	FuncID_systemstack
+	FuncID_systemstack_switch
+	FuncID_wrapper // any autogenerated code (hash/eq algorithms, method wrappers, etc.)
+)
+
+var funcIDs = map[string]FuncID{
+	"abort":            FuncID_abort,
+	"asmcgocall":       FuncID_asmcgocall,
+	"asyncPreempt":     FuncID_asyncPreempt,
+	"cgocallback":      FuncID_cgocallback,
+	"debugCallV2":      FuncID_debugCallV2,
+	"gcBgMarkWorker":   FuncID_gcBgMarkWorker,
+	"go":               FuncID_rt0_go,
+	"goexit":           FuncID_goexit,
+	"gogo":             FuncID_gogo,
+	"gopanic":          FuncID_gopanic,
+	"handleAsyncEvent": FuncID_handleAsyncEvent,
+	"main":             FuncID_runtime_main,
+	"mcall":            FuncID_mcall,
+	"morestack":        FuncID_morestack,
+	"mstart":           FuncID_mstart,
+	"panicwrap":        FuncID_panicwrap,
+	"runfinq":          FuncID_runfinq,
+	"sigpanic":         FuncID_sigpanic,
+	"switch":           FuncID_systemstack_switch,
+	"systemstack":      FuncID_systemstack,
+
+	// Don't show in call stack but otherwise not special.
+	"deferreturn":       FuncID_wrapper,
+	"runOpenDeferFrame": FuncID_wrapper,
+	"deferCallSave":     FuncID_wrapper,
+}
+
+// Get the function ID for the named function in the named file.
+// The function should be package-qualified.
+func GetFuncID(name string, isWrapper bool) FuncID {
+	if isWrapper {
+		return FuncID_wrapper
+	}
+	if strings.HasPrefix(name, "runtime.") {
+		if id, ok := funcIDs[name[len("runtime."):]]; ok {
+			return id
+		}
+	}
+	return FuncID_normal
+}
diff --git a/src/cmd/internal/objabi/head.go b/src/cmd/internal/objabi/head.go
new file mode 100644
index 0000000..48ff292
--- /dev/null
+++ b/src/cmd/internal/objabi/head.go
@@ -0,0 +1,109 @@
+// Derived from Inferno utils/6l/l.h and related files.
+// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/l.h
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors. All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package objabi
+
+import "fmt"
+
+// HeadType is the executable header type.
+type HeadType uint8
+
+const (
+	Hunknown HeadType = iota
+	Hdarwin
+	Hdragonfly
+	Hfreebsd
+	Hjs
+	Hlinux
+	Hnetbsd
+	Hopenbsd
+	Hplan9
+	Hsolaris
+	Hwindows
+	Haix
+)
+
+func (h *HeadType) Set(s string) error {
+	switch s {
+	case "aix":
+		*h = Haix
+	case "darwin", "ios":
+		*h = Hdarwin
+	case "dragonfly":
+		*h = Hdragonfly
+	case "freebsd":
+		*h = Hfreebsd
+	case "js":
+		*h = Hjs
+	case "linux", "android":
+		*h = Hlinux
+	case "netbsd":
+		*h = Hnetbsd
+	case "openbsd":
+		*h = Hopenbsd
+	case "plan9":
+		*h = Hplan9
+	case "illumos", "solaris":
+		*h = Hsolaris
+	case "windows":
+		*h = Hwindows
+	default:
+		return fmt.Errorf("invalid headtype: %q", s)
+	}
+	return nil
+}
+
+func (h *HeadType) String() string {
+	switch *h {
+	case Haix:
+		return "aix"
+	case Hdarwin:
+		return "darwin"
+	case Hdragonfly:
+		return "dragonfly"
+	case Hfreebsd:
+		return "freebsd"
+	case Hjs:
+		return "js"
+	case Hlinux:
+		return "linux"
+	case Hnetbsd:
+		return "netbsd"
+	case Hopenbsd:
+		return "openbsd"
+	case Hplan9:
+		return "plan9"
+	case Hsolaris:
+		return "solaris"
+	case Hwindows:
+		return "windows"
+	}
+	return fmt.Sprintf("HeadType(%d)", *h)
+}
diff --git a/src/cmd/internal/objabi/line.go b/src/cmd/internal/objabi/line.go
new file mode 100644
index 0000000..0b1e0bb
--- /dev/null
+++ b/src/cmd/internal/objabi/line.go
@@ -0,0 +1,126 @@
+// 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.
+
+package objabi
+
+import (
+	"internal/buildcfg"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// WorkingDir returns the current working directory
+// (or "/???" if the directory cannot be identified),
+// with "/" as separator.
+func WorkingDir() string {
+	var path string
+	path, _ = os.Getwd()
+	if path == "" {
+		path = "/???"
+	}
+	return filepath.ToSlash(path)
+}
+
+// AbsFile returns the absolute filename for file in the given directory,
+// as rewritten by the rewrites argument.
+// For unrewritten paths, AbsFile rewrites a leading $GOROOT prefix to the literal "$GOROOT".
+// If the resulting path is the empty string, the result is "??".
+//
+// The rewrites argument is a ;-separated list of rewrites.
+// Each rewrite is of the form "prefix" or "prefix=>replace",
+// where prefix must match a leading sequence of path elements
+// and is either removed entirely or replaced by the replacement.
+func AbsFile(dir, file, rewrites string) string {
+	abs := file
+	if dir != "" && !filepath.IsAbs(file) {
+		abs = filepath.Join(dir, file)
+	}
+
+	abs, rewritten := ApplyRewrites(abs, rewrites)
+	if !rewritten && hasPathPrefix(abs, buildcfg.GOROOT) {
+		abs = "$GOROOT" + abs[len(buildcfg.GOROOT):]
+	}
+
+	if abs == "" {
+		abs = "??"
+	}
+	return abs
+}
+
+// ApplyRewrites returns the filename for file in the given directory,
+// as rewritten by the rewrites argument.
+//
+// The rewrites argument is a ;-separated list of rewrites.
+// Each rewrite is of the form "prefix" or "prefix=>replace",
+// where prefix must match a leading sequence of path elements
+// and is either removed entirely or replaced by the replacement.
+func ApplyRewrites(file, rewrites string) (string, bool) {
+	start := 0
+	for i := 0; i <= len(rewrites); i++ {
+		if i == len(rewrites) || rewrites[i] == ';' {
+			if new, ok := applyRewrite(file, rewrites[start:i]); ok {
+				return new, true
+			}
+			start = i + 1
+		}
+	}
+
+	return file, false
+}
+
+// applyRewrite applies the rewrite to the path,
+// returning the rewritten path and a boolean
+// indicating whether the rewrite applied at all.
+func applyRewrite(path, rewrite string) (string, bool) {
+	prefix, replace := rewrite, ""
+	if j := strings.LastIndex(rewrite, "=>"); j >= 0 {
+		prefix, replace = rewrite[:j], rewrite[j+len("=>"):]
+	}
+
+	if prefix == "" || !hasPathPrefix(path, prefix) {
+		return path, false
+	}
+	if len(path) == len(prefix) {
+		return replace, true
+	}
+	if replace == "" {
+		return path[len(prefix)+1:], true
+	}
+	return replace + path[len(prefix):], true
+}
+
+// Does s have t as a path prefix?
+// That is, does s == t or does s begin with t followed by a slash?
+// For portability, we allow ASCII case folding, so that hasPathPrefix("a/b/c", "A/B") is true.
+// Similarly, we allow slash folding, so that hasPathPrefix("a/b/c", "a\\b") is true.
+// We do not allow full Unicode case folding, for fear of causing more confusion
+// or harm than good. (For an example of the kinds of things that can go wrong,
+// see http://article.gmane.org/gmane.linux.kernel/1853266.)
+func hasPathPrefix(s string, t string) bool {
+	if len(t) > len(s) {
+		return false
+	}
+	var i int
+	for i = 0; i < len(t); i++ {
+		cs := int(s[i])
+		ct := int(t[i])
+		if 'A' <= cs && cs <= 'Z' {
+			cs += 'a' - 'A'
+		}
+		if 'A' <= ct && ct <= 'Z' {
+			ct += 'a' - 'A'
+		}
+		if cs == '\\' {
+			cs = '/'
+		}
+		if ct == '\\' {
+			ct = '/'
+		}
+		if cs != ct {
+			return false
+		}
+	}
+	return i >= len(s) || s[i] == '/' || s[i] == '\\'
+}
diff --git a/src/cmd/internal/objabi/line_test.go b/src/cmd/internal/objabi/line_test.go
new file mode 100644
index 0000000..1fa0ff1
--- /dev/null
+++ b/src/cmd/internal/objabi/line_test.go
@@ -0,0 +1,50 @@
+// Copyright 2019 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 objabi
+
+import (
+	"path/filepath"
+	"runtime"
+	"testing"
+)
+
+// On Windows, "/foo" is reported as a relative path
+// (it is relative to the current drive letter),
+// so we need add a drive letter to test absolute path cases.
+func drive() string {
+	if runtime.GOOS == "windows" {
+		return "c:"
+	}
+	return ""
+}
+
+var absFileTests = []struct {
+	dir      string
+	file     string
+	rewrites string
+	abs      string
+}{
+	{"/d", "f", "", "/d/f"},
+	{"/d", drive() + "/f", "", drive() + "/f"},
+	{"/d", "f/g", "", "/d/f/g"},
+	{"/d", drive() + "/f/g", "", drive() + "/f/g"},
+
+	{"/d", "f", "/d/f", "??"},
+	{"/d", "f/g", "/d/f", "g"},
+	{"/d", "f/g", "/d/f=>h", "h/g"},
+	{"/d", "f/g", "/d/f=>/h", "/h/g"},
+	{"/d", "f/g", "/d/f=>/h;/d/e=>/i", "/h/g"},
+	{"/d", "e/f", "/d/f=>/h;/d/e=>/i", "/i/f"},
+}
+
+func TestAbsFile(t *testing.T) {
+	for _, tt := range absFileTests {
+		abs := filepath.FromSlash(AbsFile(filepath.FromSlash(tt.dir), filepath.FromSlash(tt.file), tt.rewrites))
+		want := filepath.FromSlash(tt.abs)
+		if abs != want {
+			t.Errorf("AbsFile(%q, %q, %q) = %q, want %q", tt.dir, tt.file, tt.rewrites, abs, want)
+		}
+	}
+}
diff --git a/src/cmd/internal/objabi/path.go b/src/cmd/internal/objabi/path.go
new file mode 100644
index 0000000..aacab9a
--- /dev/null
+++ b/src/cmd/internal/objabi/path.go
@@ -0,0 +1,67 @@
+// Copyright 2017 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 objabi
+
+import "strings"
+
+// PathToPrefix converts raw string to the prefix that will be used in the
+// symbol table. All control characters, space, '%' and '"', as well as
+// non-7-bit clean bytes turn into %xx. The period needs escaping only in the
+// last segment of the path, and it makes for happier users if we escape that as
+// little as possible.
+func PathToPrefix(s string) string {
+	slash := strings.LastIndex(s, "/")
+	// check for chars that need escaping
+	n := 0
+	for r := 0; r < len(s); r++ {
+		if c := s[r]; c <= ' ' || (c == '.' && r > slash) || c == '%' || c == '"' || c >= 0x7F {
+			n++
+		}
+	}
+
+	// quick exit
+	if n == 0 {
+		return s
+	}
+
+	// escape
+	const hex = "0123456789abcdef"
+	p := make([]byte, 0, len(s)+2*n)
+	for r := 0; r < len(s); r++ {
+		if c := s[r]; c <= ' ' || (c == '.' && r > slash) || c == '%' || c == '"' || c >= 0x7F {
+			p = append(p, '%', hex[c>>4], hex[c&0xF])
+		} else {
+			p = append(p, c)
+		}
+	}
+
+	return string(p)
+}
+
+// IsRuntimePackagePath examines 'pkgpath' and returns TRUE if it
+// belongs to the collection of "runtime-related" packages, including
+// "runtime" itself, "reflect", "syscall", and the
+// "runtime/internal/*" packages. The compiler and/or assembler in
+// some cases need to be aware of when they are building such a
+// package, for example to enable features such as ABI selectors in
+// assembly sources.
+//
+// Keep in sync with cmd/dist/build.go:IsRuntimePackagePath.
+func IsRuntimePackagePath(pkgpath string) bool {
+	rval := false
+	switch pkgpath {
+	case "runtime":
+		rval = true
+	case "reflect":
+		rval = true
+	case "syscall":
+		rval = true
+	case "internal/bytealg":
+		rval = true
+	default:
+		rval = strings.HasPrefix(pkgpath, "runtime/internal")
+	}
+	return rval
+}
diff --git a/src/cmd/internal/objabi/path_test.go b/src/cmd/internal/objabi/path_test.go
new file mode 100644
index 0000000..05d7fb4
--- /dev/null
+++ b/src/cmd/internal/objabi/path_test.go
@@ -0,0 +1,33 @@
+// Copyright 2017 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 objabi
+
+import "testing"
+
+func TestPathToPrefix(t *testing.T) {
+	tests := []struct {
+		Path     string
+		Expected string
+	}{{"foo/bar/v1", "foo/bar/v1"},
+		{"foo/bar/v.1", "foo/bar/v%2e1"},
+		{"f.o.o/b.a.r/v1", "f.o.o/b.a.r/v1"},
+		{"f.o.o/b.a.r/v.1", "f.o.o/b.a.r/v%2e1"},
+		{"f.o.o/b.a.r/v..1", "f.o.o/b.a.r/v%2e%2e1"},
+		{"f.o.o/b.a.r/v..1.", "f.o.o/b.a.r/v%2e%2e1%2e"},
+		{"f.o.o/b.a.r/v%1", "f.o.o/b.a.r/v%251"},
+		{"runtime", "runtime"},
+		{"sync/atomic", "sync/atomic"},
+		{"golang.org/x/tools/godoc", "golang.org/x/tools/godoc"},
+		{"foo.bar/baz.quux", "foo.bar/baz%2equux"},
+		{"", ""},
+		{"%foo%bar", "%25foo%25bar"},
+		{"\x01\x00\x7F☺", "%01%00%7f%e2%98%ba"},
+	}
+	for _, tc := range tests {
+		if got := PathToPrefix(tc.Path); got != tc.Expected {
+			t.Errorf("expected PathToPrefix(%s) = %s, got %s", tc.Path, tc.Expected, got)
+		}
+	}
+}
diff --git a/src/cmd/internal/objabi/reloctype.go b/src/cmd/internal/objabi/reloctype.go
new file mode 100644
index 0000000..a9c3030
--- /dev/null
+++ b/src/cmd/internal/objabi/reloctype.go
@@ -0,0 +1,312 @@
+// Derived from Inferno utils/6l/l.h and related files.
+// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/l.h
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors. All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package objabi
+
+type RelocType int16
+
+//go:generate stringer -type=RelocType
+const (
+	R_ADDR RelocType = 1 + iota
+	// R_ADDRPOWER relocates a pair of "D-form" instructions (instructions with 16-bit
+	// immediates in the low half of the instruction word), usually addis followed by
+	// another add or a load, inserting the "high adjusted" 16 bits of the address of
+	// the referenced symbol into the immediate field of the first instruction and the
+	// low 16 bits into that of the second instruction.
+	R_ADDRPOWER
+	// R_ADDRARM64 relocates an adrp, add pair to compute the address of the
+	// referenced symbol.
+	R_ADDRARM64
+	// R_ADDRMIPS (only used on mips/mips64) resolves to the low 16 bits of an external
+	// address, by encoding it into the instruction.
+	R_ADDRMIPS
+	// R_ADDROFF resolves to a 32-bit offset from the beginning of the section
+	// holding the data being relocated to the referenced symbol.
+	R_ADDROFF
+	R_SIZE
+	R_CALL
+	R_CALLARM
+	R_CALLARM64
+	R_CALLIND
+	R_CALLPOWER
+	// R_CALLMIPS (only used on mips64) resolves to non-PC-relative target address
+	// of a CALL (JAL) instruction, by encoding the address into the instruction.
+	R_CALLMIPS
+	R_CONST
+	R_PCREL
+	// R_TLS_LE, used on 386, amd64, and ARM, resolves to the offset of the
+	// thread-local symbol from the thread local base and is used to implement the
+	// "local exec" model for tls access (r.Sym is not set on intel platforms but is
+	// set to a TLS symbol -- runtime.tlsg -- in the linker when externally linking).
+	R_TLS_LE
+	// R_TLS_IE, used 386, amd64, and ARM resolves to the PC-relative offset to a GOT
+	// slot containing the offset from the thread-local symbol from the thread local
+	// base and is used to implemented the "initial exec" model for tls access (r.Sym
+	// is not set on intel platforms but is set to a TLS symbol -- runtime.tlsg -- in
+	// the linker when externally linking).
+	R_TLS_IE
+	R_GOTOFF
+	R_PLT0
+	R_PLT1
+	R_PLT2
+	R_USEFIELD
+	// R_USETYPE resolves to an *rtype, but no relocation is created. The
+	// linker uses this as a signal that the pointed-to type information
+	// should be linked into the final binary, even if there are no other
+	// direct references. (This is used for types reachable by reflection.)
+	R_USETYPE
+	// R_USEIFACE marks a type is converted to an interface in the function this
+	// relocation is applied to. The target is a type descriptor.
+	// This is a marker relocation (0-sized), for the linker's reachabililty
+	// analysis.
+	R_USEIFACE
+	// R_USEIFACEMETHOD marks an interface method that is used in the function
+	// this relocation is applied to. The target is an interface type descriptor.
+	// The addend is the offset of the method in the type descriptor.
+	// This is a marker relocation (0-sized), for the linker's reachabililty
+	// analysis.
+	R_USEIFACEMETHOD
+	// Similar to R_USEIFACEMETHOD, except instead of indicating a type +
+	// method offset with Sym+Add, Sym points to a symbol containing the name
+	// of the method being called. See the description in
+	// cmd/compile/internal/reflectdata/reflect.go:MarkUsedIfaceMethod for details.
+	R_USEGENERICIFACEMETHOD
+	// R_METHODOFF resolves to a 32-bit offset from the beginning of the section
+	// holding the data being relocated to the referenced symbol.
+	// It is a variant of R_ADDROFF used when linking from the uncommonType of a
+	// *rtype, and may be set to zero by the linker if it determines the method
+	// text is unreachable by the linked program.
+	R_METHODOFF
+	// R_KEEP tells the linker to keep the referred-to symbol in the final binary
+	// if the symbol containing the R_KEEP relocation is in the final binary.
+	R_KEEP
+	R_POWER_TOC
+	R_GOTPCREL
+	// R_JMPMIPS (only used on mips64) resolves to non-PC-relative target address
+	// of a JMP instruction, by encoding the address into the instruction.
+	// The stack nosplit check ignores this since it is not a function call.
+	R_JMPMIPS
+
+	// R_DWARFSECREF resolves to the offset of the symbol from its section.
+	// Target of relocation must be size 4 (in current implementation).
+	R_DWARFSECREF
+
+	// R_DWARFFILEREF resolves to an index into the DWARF .debug_line
+	// file table for the specified file symbol. Must be applied to an
+	// attribute of form DW_FORM_data4.
+	R_DWARFFILEREF
+
+	// Platform dependent relocations. Architectures with fixed width instructions
+	// have the inherent issue that a 32-bit (or 64-bit!) displacement cannot be
+	// stuffed into a 32-bit instruction, so an address needs to be spread across
+	// several instructions, and in turn this requires a sequence of relocations, each
+	// updating a part of an instruction. This leads to relocation codes that are
+	// inherently processor specific.
+
+	// Arm64.
+
+	// Set a MOV[NZ] immediate field to bits [15:0] of the offset from the thread
+	// local base to the thread local variable defined by the referenced (thread
+	// local) symbol. Error if the offset does not fit into 16 bits.
+	R_ARM64_TLS_LE
+
+	// Relocates an ADRP; LD64 instruction sequence to load the offset between
+	// the thread local base and the thread local variable defined by the
+	// referenced (thread local) symbol from the GOT.
+	R_ARM64_TLS_IE
+
+	// R_ARM64_GOTPCREL relocates an adrp, ld64 pair to compute the address of the GOT
+	// slot of the referenced symbol.
+	R_ARM64_GOTPCREL
+
+	// R_ARM64_GOT resolves a GOT-relative instruction sequence, usually an adrp
+	// followed by another ld instruction.
+	R_ARM64_GOT
+
+	// R_ARM64_PCREL resolves a PC-relative addresses instruction sequence, usually an
+	// adrp followed by another add instruction.
+	R_ARM64_PCREL
+
+	// R_ARM64_LDST8 sets a LD/ST immediate value to bits [11:0] of a local address.
+	R_ARM64_LDST8
+
+	// R_ARM64_LDST16 sets a LD/ST immediate value to bits [11:1] of a local address.
+	R_ARM64_LDST16
+
+	// R_ARM64_LDST32 sets a LD/ST immediate value to bits [11:2] of a local address.
+	R_ARM64_LDST32
+
+	// R_ARM64_LDST64 sets a LD/ST immediate value to bits [11:3] of a local address.
+	R_ARM64_LDST64
+
+	// R_ARM64_LDST128 sets a LD/ST immediate value to bits [11:4] of a local address.
+	R_ARM64_LDST128
+
+	// PPC64.
+
+	// R_POWER_TLS_LE is used to implement the "local exec" model for tls
+	// access. It resolves to the offset of the thread-local symbol from the
+	// thread pointer (R13) and is split against a pair of instructions to
+	// support a 32 bit displacement.
+	R_POWER_TLS_LE
+
+	// R_POWER_TLS_IE is used to implement the "initial exec" model for tls access. It
+	// relocates a D-form, DS-form instruction sequence like R_ADDRPOWER_DS. It
+	// inserts to the offset of GOT slot for the thread-local symbol from the TOC (the
+	// GOT slot is filled by the dynamic linker with the offset of the thread-local
+	// symbol from the thread pointer (R13)).
+	R_POWER_TLS_IE
+
+	// R_POWER_TLS marks an X-form instruction such as "ADD R3,R13,R4" as completing
+	// a sequence of GOT-relative relocations to compute a TLS address. This can be
+	// used by the system linker to to rewrite the GOT-relative TLS relocation into a
+	// simpler thread-pointer relative relocation. See table 3.26 and 3.28 in the
+	// ppc64 elfv2 1.4 ABI on this transformation.  Likewise, the second argument
+	// (usually called RB in X-form instructions) is assumed to be R13.
+	R_POWER_TLS
+
+	// R_ADDRPOWER_DS is similar to R_ADDRPOWER above, but assumes the second
+	// instruction is a "DS-form" instruction, which has an immediate field occupying
+	// bits [15:2] of the instruction word. Bits [15:2] of the address of the
+	// relocated symbol are inserted into this field; it is an error if the last two
+	// bits of the address are not 0.
+	R_ADDRPOWER_DS
+
+	// R_ADDRPOWER_PCREL relocates a D-form, DS-form instruction sequence like
+	// R_ADDRPOWER_DS but inserts the offset of the GOT slot for the referenced symbol
+	// from the TOC rather than the symbol's address.
+	R_ADDRPOWER_GOT
+
+	// R_ADDRPOWER_PCREL relocates two D-form instructions like R_ADDRPOWER, but
+	// inserts the displacement from the place being relocated to the address of the
+	// relocated symbol instead of just its address.
+	R_ADDRPOWER_PCREL
+
+	// R_ADDRPOWER_TOCREL relocates two D-form instructions like R_ADDRPOWER, but
+	// inserts the offset from the TOC to the address of the relocated symbol
+	// rather than the symbol's address.
+	R_ADDRPOWER_TOCREL
+
+	// R_ADDRPOWER_TOCREL relocates a D-form, DS-form instruction sequence like
+	// R_ADDRPOWER_DS but inserts the offset from the TOC to the address of the
+	// relocated symbol rather than the symbol's address.
+	R_ADDRPOWER_TOCREL_DS
+
+	// RISC-V.
+
+	// R_RISCV_CALL relocates a J-type instruction with a 21 bit PC-relative
+	// address.
+	R_RISCV_CALL
+
+	// R_RISCV_CALL_TRAMP is the same as R_RISCV_CALL but denotes the use of a
+	// trampoline, which we may be able to avoid during relocation. These are
+	// only used by the linker and are not emitted by the compiler or assembler.
+	R_RISCV_CALL_TRAMP
+
+	// R_RISCV_PCREL_ITYPE resolves a 32-bit PC-relative address using an
+	// AUIPC + I-type instruction pair.
+	R_RISCV_PCREL_ITYPE
+
+	// R_RISCV_PCREL_STYPE resolves a 32-bit PC-relative address using an
+	// AUIPC + S-type instruction pair.
+	R_RISCV_PCREL_STYPE
+
+	// R_RISCV_TLS_IE_ITYPE resolves a 32-bit TLS initial-exec TOC offset
+	// address using an AUIPC + I-type instruction pair.
+	R_RISCV_TLS_IE_ITYPE
+
+	// R_RISCV_TLS_IE_STYPE resolves a 32-bit TLS initial-exec TOC offset
+	// address using an AUIPC + S-type instruction pair.
+	R_RISCV_TLS_IE_STYPE
+
+	// R_PCRELDBL relocates s390x 2-byte aligned PC-relative addresses.
+	// TODO(mundaym): remove once variants can be serialized - see issue 14218.
+	R_PCRELDBL
+
+	// R_ADDRMIPSU (only used on mips/mips64) resolves to the sign-adjusted "upper" 16
+	// bits (bit 16-31) of an external address, by encoding it into the instruction.
+	R_ADDRMIPSU
+	// R_ADDRMIPSTLS (only used on mips64) resolves to the low 16 bits of a TLS
+	// address (offset from thread pointer), by encoding it into the instruction.
+	R_ADDRMIPSTLS
+
+	// R_ADDRCUOFF resolves to a pointer-sized offset from the start of the
+	// symbol's DWARF compile unit.
+	R_ADDRCUOFF
+
+	// R_WASMIMPORT resolves to the index of the WebAssembly function import.
+	R_WASMIMPORT
+
+	// R_XCOFFREF (only used on aix/ppc64) prevents garbage collection by ld
+	// of a symbol. This isn't a real relocation, it can be placed in anywhere
+	// in a symbol and target any symbols.
+	R_XCOFFREF
+
+	// R_WEAK marks the relocation as a weak reference.
+	// A weak relocation does not make the symbol it refers to reachable,
+	// and is only honored by the linker if the symbol is in some other way
+	// reachable.
+	R_WEAK = -1 << 15
+
+	R_WEAKADDR    = R_WEAK | R_ADDR
+	R_WEAKADDROFF = R_WEAK | R_ADDROFF
+)
+
+// IsDirectCall reports whether r is a relocation for a direct call.
+// A direct call is a CALL instruction that takes the target address
+// as an immediate. The address is embedded into the instruction, possibly
+// with limited width. An indirect call is a CALL instruction that takes
+// the target address in register or memory.
+func (r RelocType) IsDirectCall() bool {
+	switch r {
+	case R_CALL, R_CALLARM, R_CALLARM64, R_CALLMIPS, R_CALLPOWER, R_RISCV_CALL, R_RISCV_CALL_TRAMP:
+		return true
+	}
+	return false
+}
+
+// IsDirectJump reports whether r is a relocation for a direct jump.
+// A direct jump is a JMP instruction that takes the target address
+// as an immediate. The address is embedded into the instruction, possibly
+// with limited width. An indirect jump is a JMP instruction that takes
+// the target address in register or memory.
+func (r RelocType) IsDirectJump() bool {
+	switch r {
+	case R_JMPMIPS:
+		return true
+	}
+	return false
+}
+
+// IsDirectCallOrJump reports whether r is a relocation for a direct
+// call or a direct jump.
+func (r RelocType) IsDirectCallOrJump() bool {
+	return r.IsDirectCall() || r.IsDirectJump()
+}
diff --git a/src/cmd/internal/objabi/reloctype_string.go b/src/cmd/internal/objabi/reloctype_string.go
new file mode 100644
index 0000000..d1b15b5
--- /dev/null
+++ b/src/cmd/internal/objabi/reloctype_string.go
@@ -0,0 +1,85 @@
+// Code generated by "stringer -type=RelocType"; DO NOT EDIT.
+
+package objabi
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[R_ADDR-1]
+	_ = x[R_ADDRPOWER-2]
+	_ = x[R_ADDRARM64-3]
+	_ = x[R_ADDRMIPS-4]
+	_ = x[R_ADDROFF-5]
+	_ = x[R_SIZE-6]
+	_ = x[R_CALL-7]
+	_ = x[R_CALLARM-8]
+	_ = x[R_CALLARM64-9]
+	_ = x[R_CALLIND-10]
+	_ = x[R_CALLPOWER-11]
+	_ = x[R_CALLMIPS-12]
+	_ = x[R_CONST-13]
+	_ = x[R_PCREL-14]
+	_ = x[R_TLS_LE-15]
+	_ = x[R_TLS_IE-16]
+	_ = x[R_GOTOFF-17]
+	_ = x[R_PLT0-18]
+	_ = x[R_PLT1-19]
+	_ = x[R_PLT2-20]
+	_ = x[R_USEFIELD-21]
+	_ = x[R_USETYPE-22]
+	_ = x[R_USEIFACE-23]
+	_ = x[R_USEIFACEMETHOD-24]
+	_ = x[R_USEGENERICIFACEMETHOD-25]
+	_ = x[R_METHODOFF-26]
+	_ = x[R_KEEP-27]
+	_ = x[R_POWER_TOC-28]
+	_ = x[R_GOTPCREL-29]
+	_ = x[R_JMPMIPS-30]
+	_ = x[R_DWARFSECREF-31]
+	_ = x[R_DWARFFILEREF-32]
+	_ = x[R_ARM64_TLS_LE-33]
+	_ = x[R_ARM64_TLS_IE-34]
+	_ = x[R_ARM64_GOTPCREL-35]
+	_ = x[R_ARM64_GOT-36]
+	_ = x[R_ARM64_PCREL-37]
+	_ = x[R_ARM64_LDST8-38]
+	_ = x[R_ARM64_LDST16-39]
+	_ = x[R_ARM64_LDST32-40]
+	_ = x[R_ARM64_LDST64-41]
+	_ = x[R_ARM64_LDST128-42]
+	_ = x[R_POWER_TLS_LE-43]
+	_ = x[R_POWER_TLS_IE-44]
+	_ = x[R_POWER_TLS-45]
+	_ = x[R_ADDRPOWER_DS-46]
+	_ = x[R_ADDRPOWER_GOT-47]
+	_ = x[R_ADDRPOWER_PCREL-48]
+	_ = x[R_ADDRPOWER_TOCREL-49]
+	_ = x[R_ADDRPOWER_TOCREL_DS-50]
+	_ = x[R_RISCV_CALL-51]
+	_ = x[R_RISCV_CALL_TRAMP-52]
+	_ = x[R_RISCV_PCREL_ITYPE-53]
+	_ = x[R_RISCV_PCREL_STYPE-54]
+	_ = x[R_RISCV_TLS_IE_ITYPE-55]
+	_ = x[R_RISCV_TLS_IE_STYPE-56]
+	_ = x[R_PCRELDBL-57]
+	_ = x[R_ADDRMIPSU-58]
+	_ = x[R_ADDRMIPSTLS-59]
+	_ = x[R_ADDRCUOFF-60]
+	_ = x[R_WASMIMPORT-61]
+	_ = x[R_XCOFFREF-62]
+}
+
+const _RelocType_name = "R_ADDRR_ADDRPOWERR_ADDRARM64R_ADDRMIPSR_ADDROFFR_SIZER_CALLR_CALLARMR_CALLARM64R_CALLINDR_CALLPOWERR_CALLMIPSR_CONSTR_PCRELR_TLS_LER_TLS_IER_GOTOFFR_PLT0R_PLT1R_PLT2R_USEFIELDR_USETYPER_USEIFACER_USEIFACEMETHODR_USEGENERICIFACEMETHODR_METHODOFFR_KEEPR_POWER_TOCR_GOTPCRELR_JMPMIPSR_DWARFSECREFR_DWARFFILEREFR_ARM64_TLS_LER_ARM64_TLS_IER_ARM64_GOTPCRELR_ARM64_GOTR_ARM64_PCRELR_ARM64_LDST8R_ARM64_LDST16R_ARM64_LDST32R_ARM64_LDST64R_ARM64_LDST128R_POWER_TLS_LER_POWER_TLS_IER_POWER_TLSR_ADDRPOWER_DSR_ADDRPOWER_GOTR_ADDRPOWER_PCRELR_ADDRPOWER_TOCRELR_ADDRPOWER_TOCREL_DSR_RISCV_CALLR_RISCV_CALL_TRAMPR_RISCV_PCREL_ITYPER_RISCV_PCREL_STYPER_RISCV_TLS_IE_ITYPER_RISCV_TLS_IE_STYPER_PCRELDBLR_ADDRMIPSUR_ADDRMIPSTLSR_ADDRCUOFFR_WASMIMPORTR_XCOFFREF"
+
+var _RelocType_index = [...]uint16{0, 6, 17, 28, 38, 47, 53, 59, 68, 79, 88, 99, 109, 116, 123, 131, 139, 147, 153, 159, 165, 175, 184, 194, 210, 233, 244, 250, 261, 271, 280, 293, 307, 321, 335, 351, 362, 375, 388, 402, 416, 430, 445, 459, 473, 484, 498, 513, 530, 548, 569, 581, 599, 618, 637, 657, 677, 687, 698, 711, 722, 734, 744}
+
+func (i RelocType) String() string {
+	i -= 1
+	if i < 0 || i >= RelocType(len(_RelocType_index)-1) {
+		return "RelocType(" + strconv.FormatInt(int64(i+1), 10) + ")"
+	}
+	return _RelocType_name[_RelocType_index[i]:_RelocType_index[i+1]]
+}
diff --git a/src/cmd/internal/objabi/stack.go b/src/cmd/internal/objabi/stack.go
new file mode 100644
index 0000000..0c82a7c
--- /dev/null
+++ b/src/cmd/internal/objabi/stack.go
@@ -0,0 +1,31 @@
+// Copyright 2011 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 objabi
+
+import "internal/buildcfg"
+
+// For the linkers. Must match Go definitions.
+
+const (
+	STACKSYSTEM = 0
+	StackSystem = STACKSYSTEM
+	StackBig    = 4096
+	StackSmall  = 128
+)
+
+// Initialize StackGuard and StackLimit according to target system.
+var StackGuard = 928*stackGuardMultiplier() + StackSystem
+var StackLimit = StackGuard - StackSystem - StackSmall
+
+// stackGuardMultiplier returns a multiplier to apply to the default
+// stack guard size. Larger multipliers are used for non-optimized
+// builds that have larger stack frames or for specific targets.
+func stackGuardMultiplier() int {
+	// On AIX, a larger stack is needed for syscalls.
+	if buildcfg.GOOS == "aix" {
+		return 2
+	}
+	return stackGuardMultiplierDefault
+}
diff --git a/src/cmd/internal/objabi/symkind.go b/src/cmd/internal/objabi/symkind.go
new file mode 100644
index 0000000..28f430f
--- /dev/null
+++ b/src/cmd/internal/objabi/symkind.go
@@ -0,0 +1,72 @@
+// Derived from Inferno utils/6l/l.h and related files.
+// https://bitbucket.org/inferno-os/inferno-os/src/master/utils/6l/l.h
+//
+//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
+//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
+//	Portions Copyright © 1997-1999 Vita Nuova Limited
+//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
+//	Portions Copyright © 2004,2006 Bruce Ellis
+//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
+//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
+//	Portions Copyright © 2009 The Go Authors. All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package objabi
+
+// A SymKind describes the kind of memory represented by a symbol.
+type SymKind uint8
+
+// Defined SymKind values.
+// These are used to index into cmd/link/internal/sym/AbiSymKindToSymKind
+//
+// TODO(rsc): Give idiomatic Go names.
+//go:generate stringer -type=SymKind
+const (
+	// An otherwise invalid zero value for the type
+	Sxxx SymKind = iota
+	// Executable instructions
+	STEXT
+	// Read only static data
+	SRODATA
+	// Static data that does not contain any pointers
+	SNOPTRDATA
+	// Static data
+	SDATA
+	// Statically data that is initially all 0s
+	SBSS
+	// Statically data that is initially all 0s and does not contain pointers
+	SNOPTRBSS
+	// Thread-local data that is initially all 0s
+	STLSBSS
+	// Debugging data
+	SDWARFCUINFO
+	SDWARFCONST
+	SDWARFFCN
+	SDWARFABSFCN
+	SDWARFTYPE
+	SDWARFVAR
+	SDWARFRANGE
+	SDWARFLOC
+	SDWARFLINES
+	// Coverage instrumentation counter for libfuzzer.
+	SLIBFUZZER_EXTRA_COUNTER
+	// Update cmd/link/internal/sym/AbiSymKindToSymKind for new SymKind values.
+
+)
diff --git a/src/cmd/internal/objabi/symkind_string.go b/src/cmd/internal/objabi/symkind_string.go
new file mode 100644
index 0000000..c90cf43
--- /dev/null
+++ b/src/cmd/internal/objabi/symkind_string.go
@@ -0,0 +1,40 @@
+// Code generated by "stringer -type=SymKind"; DO NOT EDIT.
+
+package objabi
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[Sxxx-0]
+	_ = x[STEXT-1]
+	_ = x[SRODATA-2]
+	_ = x[SNOPTRDATA-3]
+	_ = x[SDATA-4]
+	_ = x[SBSS-5]
+	_ = x[SNOPTRBSS-6]
+	_ = x[STLSBSS-7]
+	_ = x[SDWARFCUINFO-8]
+	_ = x[SDWARFCONST-9]
+	_ = x[SDWARFFCN-10]
+	_ = x[SDWARFABSFCN-11]
+	_ = x[SDWARFTYPE-12]
+	_ = x[SDWARFVAR-13]
+	_ = x[SDWARFRANGE-14]
+	_ = x[SDWARFLOC-15]
+	_ = x[SDWARFLINES-16]
+	_ = x[SLIBFUZZER_EXTRA_COUNTER-17]
+}
+
+const _SymKind_name = "SxxxSTEXTSRODATASNOPTRDATASDATASBSSSNOPTRBSSSTLSBSSSDWARFCUINFOSDWARFCONSTSDWARFFCNSDWARFABSFCNSDWARFTYPESDWARFVARSDWARFRANGESDWARFLOCSDWARFLINESSLIBFUZZER_EXTRA_COUNTER"
+
+var _SymKind_index = [...]uint8{0, 4, 9, 16, 26, 31, 35, 44, 51, 63, 74, 83, 95, 105, 114, 125, 134, 145, 169}
+
+func (i SymKind) String() string {
+	if i >= SymKind(len(_SymKind_index)-1) {
+		return "SymKind(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _SymKind_name[_SymKind_index[i]:_SymKind_index[i+1]]
+}
diff --git a/src/cmd/internal/objabi/typekind.go b/src/cmd/internal/objabi/typekind.go
new file mode 100644
index 0000000..990ff18
--- /dev/null
+++ b/src/cmd/internal/objabi/typekind.go
@@ -0,0 +1,40 @@
+// Copyright 2012 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 objabi
+
+// Must match runtime and reflect.
+// Included by cmd/gc.
+
+const (
+	KindBool = 1 + iota
+	KindInt
+	KindInt8
+	KindInt16
+	KindInt32
+	KindInt64
+	KindUint
+	KindUint8
+	KindUint16
+	KindUint32
+	KindUint64
+	KindUintptr
+	KindFloat32
+	KindFloat64
+	KindComplex64
+	KindComplex128
+	KindArray
+	KindChan
+	KindFunc
+	KindInterface
+	KindMap
+	KindPtr
+	KindSlice
+	KindString
+	KindStruct
+	KindUnsafePointer
+	KindDirectIface = 1 << 5
+	KindGCProg      = 1 << 6
+	KindMask        = (1 << 5) - 1
+)
diff --git a/src/cmd/internal/objabi/util.go b/src/cmd/internal/objabi/util.go
new file mode 100644
index 0000000..6bfa25a
--- /dev/null
+++ b/src/cmd/internal/objabi/util.go
@@ -0,0 +1,26 @@
+// Copyright 2015 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 objabi
+
+import (
+	"fmt"
+	"strings"
+
+	"internal/buildcfg"
+)
+
+const (
+	ElfRelocOffset   = 256
+	MachoRelocOffset = 2048    // reserve enough space for ELF relocations
+	GlobalDictPrefix = ".dict" // prefix for names of global dictionaries
+)
+
+// HeaderString returns the toolchain configuration string written in
+// Go object headers. This string ensures we don't attempt to import
+// or link object files that are incompatible with each other. This
+// string always starts with "go object ".
+func HeaderString() string {
+	return fmt.Sprintf("go object %s %s %s X:%s\n", buildcfg.GOOS, buildcfg.GOARCH, buildcfg.Version, strings.Join(buildcfg.EnabledExperiments(), ","))
+}