cmd/go: remove support for -buildmode=shared

It never worked in module mode (or with a read-only GOROOT).
A proposal to drop it was filed (and approved) in
https://golang.org/issue/47788.

Fixes #47788

Change-Id: I0c12f38eb0c5dfe9384fbdb49ed202301fa4273d
Reviewed-on: https://go-review.googlesource.com/c/go/+/359096
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
diff --git a/doc/go1.18.html b/doc/go1.18.html
index 985689c..63a6ed8 100644
--- a/doc/go1.18.html
+++ b/doc/go1.18.html
@@ -89,6 +89,13 @@
   package.
 </p>
 
+<p><!-- golang.org/issue/47788 -->
+  The <code>go</code> command no longer supports <code>-linkshared</code>
+  and <code>-buildmode=shared</code>.
+  (<code>shared<code> building and linking has never worked in module mode or
+  when <code>GOROOT</code> is not writable.)
+<p>
+
 <p>
   TODO: complete this section, or delete if not needed
 </p>
diff --git a/misc/cgo/testshared/overlaydir_test.go b/misc/cgo/testshared/overlaydir_test.go
deleted file mode 100644
index eb587a2..0000000
--- a/misc/cgo/testshared/overlaydir_test.go
+++ /dev/null
@@ -1,78 +0,0 @@
-// 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 shared_test
-
-import (
-	"io"
-	"os"
-	"path/filepath"
-	"strings"
-)
-
-// overlayDir makes a minimal-overhead copy of srcRoot in which new files may be added.
-//
-// TODO: Once we no longer need to support the misc module in GOPATH mode,
-// factor this function out into a package to reduce duplication.
-func overlayDir(dstRoot, srcRoot string) error {
-	dstRoot = filepath.Clean(dstRoot)
-	if err := os.MkdirAll(dstRoot, 0777); err != nil {
-		return err
-	}
-
-	srcRoot, err := filepath.Abs(srcRoot)
-	if err != nil {
-		return err
-	}
-
-	return filepath.Walk(srcRoot, func(srcPath string, info os.FileInfo, err error) error {
-		if err != nil || srcPath == srcRoot {
-			return err
-		}
-
-		suffix := strings.TrimPrefix(srcPath, srcRoot)
-		for len(suffix) > 0 && suffix[0] == filepath.Separator {
-			suffix = suffix[1:]
-		}
-		dstPath := filepath.Join(dstRoot, suffix)
-
-		perm := info.Mode() & os.ModePerm
-		if info.Mode()&os.ModeSymlink != 0 {
-			info, err = os.Stat(srcPath)
-			if err != nil {
-				return err
-			}
-			perm = info.Mode() & os.ModePerm
-		}
-
-		// Always copy directories (don't symlink them).
-		// If we add a file in the overlay, we don't want to add it in the original.
-		if info.IsDir() {
-			return os.MkdirAll(dstPath, perm|0200)
-		}
-
-		// If the OS supports symlinks, use them instead of copying bytes.
-		if err := os.Symlink(srcPath, dstPath); err == nil {
-			return nil
-		}
-
-		// Otherwise, copy the bytes.
-		src, err := os.Open(srcPath)
-		if err != nil {
-			return err
-		}
-		defer src.Close()
-
-		dst, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE|os.O_EXCL, perm)
-		if err != nil {
-			return err
-		}
-
-		_, err = io.Copy(dst, src)
-		if closeErr := dst.Close(); err == nil {
-			err = closeErr
-		}
-		return err
-	})
-}
diff --git a/misc/cgo/testshared/shared_test.go b/misc/cgo/testshared/shared_test.go
deleted file mode 100644
index 672811f..0000000
--- a/misc/cgo/testshared/shared_test.go
+++ /dev/null
@@ -1,1080 +0,0 @@
-// 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 shared_test
-
-import (
-	"bufio"
-	"bytes"
-	"debug/elf"
-	"encoding/binary"
-	"flag"
-	"fmt"
-	"go/build"
-	"io"
-	"log"
-	"os"
-	"os/exec"
-	"path/filepath"
-	"regexp"
-	"runtime"
-	"sort"
-	"strings"
-	"testing"
-	"time"
-)
-
-var gopathInstallDir, gorootInstallDir string
-
-// This is the smallest set of packages we can link into a shared
-// library (runtime/cgo is built implicitly).
-var minpkgs = []string{"runtime", "sync/atomic"}
-var soname = "libruntime,sync-atomic.so"
-
-var testX = flag.Bool("testx", false, "if true, pass -x to 'go' subcommands invoked by the test")
-var testWork = flag.Bool("testwork", false, "if true, log and do not delete the temporary working directory")
-
-// run runs a command and calls t.Errorf if it fails.
-func run(t *testing.T, msg string, args ...string) {
-	runWithEnv(t, msg, nil, args...)
-}
-
-// runWithEnv runs a command under the given environment and calls t.Errorf if it fails.
-func runWithEnv(t *testing.T, msg string, env []string, args ...string) {
-	c := exec.Command(args[0], args[1:]...)
-	if len(env) != 0 {
-		c.Env = append(os.Environ(), env...)
-	}
-	if output, err := c.CombinedOutput(); err != nil {
-		t.Errorf("executing %s (%s) failed %s:\n%s", strings.Join(args, " "), msg, err, output)
-	}
-}
-
-// goCmd invokes the go tool with the installsuffix set up by TestMain. It calls
-// t.Fatalf if the command fails.
-func goCmd(t *testing.T, args ...string) string {
-	newargs := []string{args[0]}
-	if *testX {
-		newargs = append(newargs, "-x")
-	}
-	newargs = append(newargs, args[1:]...)
-	c := exec.Command("go", newargs...)
-	stderr := new(strings.Builder)
-	c.Stderr = stderr
-
-	if testing.Verbose() && t == nil {
-		fmt.Fprintf(os.Stderr, "+ go %s\n", strings.Join(args, " "))
-		c.Stderr = os.Stderr
-	}
-	output, err := c.Output()
-
-	if err != nil {
-		if t != nil {
-			t.Helper()
-			t.Fatalf("executing %s failed %v:\n%s", strings.Join(c.Args, " "), err, stderr)
-		} else {
-			// Panic instead of using log.Fatalf so that deferred cleanup may run in testMain.
-			log.Panicf("executing %s failed %v:\n%s", strings.Join(c.Args, " "), err, stderr)
-		}
-	}
-	if testing.Verbose() && t != nil {
-		t.Logf("go %s", strings.Join(args, " "))
-		if stderr.Len() > 0 {
-			t.Logf("%s", stderr)
-		}
-	}
-	return string(bytes.TrimSpace(output))
-}
-
-// TestMain calls testMain so that the latter can use defer (TestMain exits with os.Exit).
-func testMain(m *testing.M) (int, error) {
-	workDir, err := os.MkdirTemp("", "shared_test")
-	if err != nil {
-		return 0, err
-	}
-	if *testWork || testing.Verbose() {
-		fmt.Printf("+ mkdir -p %s\n", workDir)
-	}
-	if !*testWork {
-		defer os.RemoveAll(workDir)
-	}
-
-	// Some tests need to edit the source in GOPATH, so copy this directory to a
-	// temporary directory and chdir to that.
-	gopath := filepath.Join(workDir, "gopath")
-	modRoot, err := cloneTestdataModule(gopath)
-	if err != nil {
-		return 0, err
-	}
-	if testing.Verbose() {
-		fmt.Printf("+ export GOPATH=%s\n", gopath)
-		fmt.Printf("+ cd %s\n", modRoot)
-	}
-	os.Setenv("GOPATH", gopath)
-	// Explicitly override GOBIN as well, in case it was set through a GOENV file.
-	os.Setenv("GOBIN", filepath.Join(gopath, "bin"))
-	os.Chdir(modRoot)
-	os.Setenv("PWD", modRoot)
-
-	// The test also needs to install libraries into GOROOT/pkg, so copy the
-	// subset of GOROOT that we need.
-	//
-	// TODO(golang.org/issue/28553): Rework -buildmode=shared so that it does not
-	// need to write to GOROOT.
-	goroot := filepath.Join(workDir, "goroot")
-	if err := cloneGOROOTDeps(goroot); err != nil {
-		return 0, err
-	}
-	if testing.Verbose() {
-		fmt.Fprintf(os.Stderr, "+ export GOROOT=%s\n", goroot)
-	}
-	os.Setenv("GOROOT", goroot)
-
-	myContext := build.Default
-	myContext.GOROOT = goroot
-	myContext.GOPATH = gopath
-	runtimeP, err := myContext.Import("runtime", ".", build.ImportComment)
-	if err != nil {
-		return 0, fmt.Errorf("import failed: %v", err)
-	}
-	gorootInstallDir = runtimeP.PkgTargetRoot + "_dynlink"
-
-	// All tests depend on runtime being built into a shared library. Because
-	// that takes a few seconds, do it here and have all tests use the version
-	// built here.
-	goCmd(nil, append([]string{"install", "-buildmode=shared"}, minpkgs...)...)
-
-	myContext.InstallSuffix = "_dynlink"
-	depP, err := myContext.Import("./depBase", ".", build.ImportComment)
-	if err != nil {
-		return 0, fmt.Errorf("import failed: %v", err)
-	}
-	if depP.PkgTargetRoot == "" {
-		gopathInstallDir = filepath.Dir(goCmd(nil, "list", "-buildmode=shared", "-f", "{{.Target}}", "./depBase"))
-	} else {
-		gopathInstallDir = filepath.Join(depP.PkgTargetRoot, "testshared")
-	}
-	return m.Run(), nil
-}
-
-func TestMain(m *testing.M) {
-	log.SetFlags(log.Lshortfile)
-	flag.Parse()
-
-	exitCode, err := testMain(m)
-	if err != nil {
-		log.Fatal(err)
-	}
-	os.Exit(exitCode)
-}
-
-// cloneTestdataModule clones the packages from src/testshared into gopath.
-// It returns the directory within gopath at which the module root is located.
-func cloneTestdataModule(gopath string) (string, error) {
-	modRoot := filepath.Join(gopath, "src", "testshared")
-	if err := overlayDir(modRoot, "testdata"); err != nil {
-		return "", err
-	}
-	if err := os.WriteFile(filepath.Join(modRoot, "go.mod"), []byte("module testshared\n"), 0644); err != nil {
-		return "", err
-	}
-	return modRoot, nil
-}
-
-// cloneGOROOTDeps copies (or symlinks) the portions of GOROOT/src and
-// GOROOT/pkg relevant to this test into the given directory.
-// It must be run from within the testdata module.
-func cloneGOROOTDeps(goroot string) error {
-	oldGOROOT := strings.TrimSpace(goCmd(nil, "env", "GOROOT"))
-	if oldGOROOT == "" {
-		return fmt.Errorf("go env GOROOT returned an empty string")
-	}
-
-	// Before we clone GOROOT, figure out which packages we need to copy over.
-	listArgs := []string{
-		"list",
-		"-deps",
-		"-f", "{{if and .Standard (not .ForTest)}}{{.ImportPath}}{{end}}",
-	}
-	stdDeps := goCmd(nil, append(listArgs, minpkgs...)...)
-	testdataDeps := goCmd(nil, append(listArgs, "-test", "./...")...)
-
-	pkgs := append(strings.Split(strings.TrimSpace(stdDeps), "\n"),
-		strings.Split(strings.TrimSpace(testdataDeps), "\n")...)
-	sort.Strings(pkgs)
-	var pkgRoots []string
-	for _, pkg := range pkgs {
-		parentFound := false
-		for _, prev := range pkgRoots {
-			if strings.HasPrefix(pkg, prev) {
-				// We will copy in the source for pkg when we copy in prev.
-				parentFound = true
-				break
-			}
-		}
-		if !parentFound {
-			pkgRoots = append(pkgRoots, pkg)
-		}
-	}
-
-	gorootDirs := []string{
-		"pkg/tool",
-		"pkg/include",
-	}
-	for _, pkg := range pkgRoots {
-		gorootDirs = append(gorootDirs, filepath.Join("src", pkg))
-	}
-
-	for _, dir := range gorootDirs {
-		if testing.Verbose() {
-			fmt.Fprintf(os.Stderr, "+ cp -r %s %s\n", filepath.Join(oldGOROOT, dir), filepath.Join(goroot, dir))
-		}
-		if err := overlayDir(filepath.Join(goroot, dir), filepath.Join(oldGOROOT, dir)); err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
-
-// The shared library was built at the expected location.
-func TestSOBuilt(t *testing.T) {
-	_, err := os.Stat(filepath.Join(gorootInstallDir, soname))
-	if err != nil {
-		t.Error(err)
-	}
-}
-
-func hasDynTag(f *elf.File, tag elf.DynTag) bool {
-	ds := f.SectionByType(elf.SHT_DYNAMIC)
-	if ds == nil {
-		return false
-	}
-	d, err := ds.Data()
-	if err != nil {
-		return false
-	}
-	for len(d) > 0 {
-		var t elf.DynTag
-		switch f.Class {
-		case elf.ELFCLASS32:
-			t = elf.DynTag(f.ByteOrder.Uint32(d[0:4]))
-			d = d[8:]
-		case elf.ELFCLASS64:
-			t = elf.DynTag(f.ByteOrder.Uint64(d[0:8]))
-			d = d[16:]
-		}
-		if t == tag {
-			return true
-		}
-	}
-	return false
-}
-
-// The shared library does not have relocations against the text segment.
-func TestNoTextrel(t *testing.T) {
-	sopath := filepath.Join(gorootInstallDir, soname)
-	f, err := elf.Open(sopath)
-	if err != nil {
-		t.Fatal("elf.Open failed: ", err)
-	}
-	defer f.Close()
-	if hasDynTag(f, elf.DT_TEXTREL) {
-		t.Errorf("%s has DT_TEXTREL set", soname)
-	}
-}
-
-// The shared library does not contain symbols called ".dup"
-// (See golang.org/issue/14841.)
-func TestNoDupSymbols(t *testing.T) {
-	sopath := filepath.Join(gorootInstallDir, soname)
-	f, err := elf.Open(sopath)
-	if err != nil {
-		t.Fatal("elf.Open failed: ", err)
-	}
-	defer f.Close()
-	syms, err := f.Symbols()
-	if err != nil {
-		t.Errorf("error reading symbols %v", err)
-		return
-	}
-	for _, s := range syms {
-		if s.Name == ".dup" {
-			t.Fatalf("%s contains symbol called .dup", sopath)
-		}
-	}
-}
-
-// The install command should have created a "shlibname" file for the
-// listed packages (and runtime/cgo, and math on arm) indicating the
-// name of the shared library containing it.
-func TestShlibnameFiles(t *testing.T) {
-	pkgs := append([]string{}, minpkgs...)
-	pkgs = append(pkgs, "runtime/cgo")
-	if runtime.GOARCH == "arm" {
-		pkgs = append(pkgs, "math")
-	}
-	for _, pkg := range pkgs {
-		shlibnamefile := filepath.Join(gorootInstallDir, pkg+".shlibname")
-		contentsb, err := os.ReadFile(shlibnamefile)
-		if err != nil {
-			t.Errorf("error reading shlibnamefile for %s: %v", pkg, err)
-			continue
-		}
-		contents := strings.TrimSpace(string(contentsb))
-		if contents != soname {
-			t.Errorf("shlibnamefile for %s has wrong contents: %q", pkg, contents)
-		}
-	}
-}
-
-// Is a given offset into the file contained in a loaded segment?
-func isOffsetLoaded(f *elf.File, offset uint64) bool {
-	for _, prog := range f.Progs {
-		if prog.Type == elf.PT_LOAD {
-			if prog.Off <= offset && offset < prog.Off+prog.Filesz {
-				return true
-			}
-		}
-	}
-	return false
-}
-
-func rnd(v int32, r int32) int32 {
-	if r <= 0 {
-		return v
-	}
-	v += r - 1
-	c := v % r
-	if c < 0 {
-		c += r
-	}
-	v -= c
-	return v
-}
-
-func readwithpad(r io.Reader, sz int32) ([]byte, error) {
-	data := make([]byte, rnd(sz, 4))
-	_, err := io.ReadFull(r, data)
-	if err != nil {
-		return nil, err
-	}
-	data = data[:sz]
-	return data, nil
-}
-
-type note struct {
-	name    string
-	tag     int32
-	desc    string
-	section *elf.Section
-}
-
-// Read all notes from f. As ELF section names are not supposed to be special, one
-// looks for a particular note by scanning all SHT_NOTE sections looking for a note
-// with a particular "name" and "tag".
-func readNotes(f *elf.File) ([]*note, error) {
-	var notes []*note
-	for _, sect := range f.Sections {
-		if sect.Type != elf.SHT_NOTE {
-			continue
-		}
-		r := sect.Open()
-		for {
-			var namesize, descsize, tag int32
-			err := binary.Read(r, f.ByteOrder, &namesize)
-			if err != nil {
-				if err == io.EOF {
-					break
-				}
-				return nil, fmt.Errorf("read namesize failed: %v", err)
-			}
-			err = binary.Read(r, f.ByteOrder, &descsize)
-			if err != nil {
-				return nil, fmt.Errorf("read descsize failed: %v", err)
-			}
-			err = binary.Read(r, f.ByteOrder, &tag)
-			if err != nil {
-				return nil, fmt.Errorf("read type failed: %v", err)
-			}
-			name, err := readwithpad(r, namesize)
-			if err != nil {
-				return nil, fmt.Errorf("read name failed: %v", err)
-			}
-			desc, err := readwithpad(r, descsize)
-			if err != nil {
-				return nil, fmt.Errorf("read desc failed: %v", err)
-			}
-			notes = append(notes, &note{name: string(name), tag: tag, desc: string(desc), section: sect})
-		}
-	}
-	return notes, nil
-}
-
-func dynStrings(t *testing.T, path string, flag elf.DynTag) []string {
-	t.Helper()
-	f, err := elf.Open(path)
-	if err != nil {
-		t.Fatalf("elf.Open(%q) failed: %v", path, err)
-	}
-	defer f.Close()
-	dynstrings, err := f.DynString(flag)
-	if err != nil {
-		t.Fatalf("DynString(%s) failed on %s: %v", flag, path, err)
-	}
-	return dynstrings
-}
-
-func AssertIsLinkedToRegexp(t *testing.T, path string, re *regexp.Regexp) {
-	t.Helper()
-	for _, dynstring := range dynStrings(t, path, elf.DT_NEEDED) {
-		if re.MatchString(dynstring) {
-			return
-		}
-	}
-	t.Errorf("%s is not linked to anything matching %v", path, re)
-}
-
-func AssertIsLinkedTo(t *testing.T, path, lib string) {
-	t.Helper()
-	AssertIsLinkedToRegexp(t, path, regexp.MustCompile(regexp.QuoteMeta(lib)))
-}
-
-func AssertHasRPath(t *testing.T, path, dir string) {
-	t.Helper()
-	for _, tag := range []elf.DynTag{elf.DT_RPATH, elf.DT_RUNPATH} {
-		for _, dynstring := range dynStrings(t, path, tag) {
-			for _, rpath := range strings.Split(dynstring, ":") {
-				if filepath.Clean(rpath) == filepath.Clean(dir) {
-					return
-				}
-			}
-		}
-	}
-	t.Errorf("%s does not have rpath %s", path, dir)
-}
-
-// Build a trivial program that links against the shared runtime and check it runs.
-func TestTrivialExecutable(t *testing.T) {
-	goCmd(t, "install", "-linkshared", "./trivial")
-	run(t, "trivial executable", "../../bin/trivial")
-	AssertIsLinkedTo(t, "../../bin/trivial", soname)
-	AssertHasRPath(t, "../../bin/trivial", gorootInstallDir)
-	checkSize(t, "../../bin/trivial", 100000) // it is 19K on linux/amd64, 100K should be enough
-}
-
-// Build a trivial program in PIE mode that links against the shared runtime and check it runs.
-func TestTrivialExecutablePIE(t *testing.T) {
-	goCmd(t, "build", "-buildmode=pie", "-o", "trivial.pie", "-linkshared", "./trivial")
-	run(t, "trivial executable", "./trivial.pie")
-	AssertIsLinkedTo(t, "./trivial.pie", soname)
-	AssertHasRPath(t, "./trivial.pie", gorootInstallDir)
-	checkSize(t, "./trivial.pie", 100000) // it is 19K on linux/amd64, 100K should be enough
-}
-
-// Check that the file size does not exceed a limit.
-func checkSize(t *testing.T, f string, limit int64) {
-	fi, err := os.Stat(f)
-	if err != nil {
-		t.Fatalf("stat failed: %v", err)
-	}
-	if sz := fi.Size(); sz > limit {
-		t.Errorf("file too large: got %d, want <= %d", sz, limit)
-	}
-}
-
-// Build a division test program and check it runs.
-func TestDivisionExecutable(t *testing.T) {
-	goCmd(t, "install", "-linkshared", "./division")
-	run(t, "division executable", "../../bin/division")
-}
-
-// Build an executable that uses cgo linked against the shared runtime and check it
-// runs.
-func TestCgoExecutable(t *testing.T) {
-	goCmd(t, "install", "-linkshared", "./execgo")
-	run(t, "cgo executable", "../../bin/execgo")
-}
-
-func checkPIE(t *testing.T, name string) {
-	f, err := elf.Open(name)
-	if err != nil {
-		t.Fatal("elf.Open failed: ", err)
-	}
-	defer f.Close()
-	if f.Type != elf.ET_DYN {
-		t.Errorf("%s has type %v, want ET_DYN", name, f.Type)
-	}
-	if hasDynTag(f, elf.DT_TEXTREL) {
-		t.Errorf("%s has DT_TEXTREL set", name)
-	}
-}
-
-func TestTrivialPIE(t *testing.T) {
-	name := "trivial_pie"
-	goCmd(t, "build", "-buildmode=pie", "-o="+name, "./trivial")
-	defer os.Remove(name)
-	run(t, name, "./"+name)
-	checkPIE(t, name)
-}
-
-func TestCgoPIE(t *testing.T) {
-	name := "cgo_pie"
-	goCmd(t, "build", "-buildmode=pie", "-o="+name, "./execgo")
-	defer os.Remove(name)
-	run(t, name, "./"+name)
-	checkPIE(t, name)
-}
-
-// Build a GOPATH package into a shared library that links against the goroot runtime
-// and an executable that links against both.
-func TestGopathShlib(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./depBase")
-	shlib := goCmd(t, "list", "-f", "{{.Shlib}}", "-buildmode=shared", "-linkshared", "./depBase")
-	AssertIsLinkedTo(t, shlib, soname)
-	goCmd(t, "install", "-linkshared", "./exe")
-	AssertIsLinkedTo(t, "../../bin/exe", soname)
-	AssertIsLinkedTo(t, "../../bin/exe", filepath.Base(shlib))
-	AssertHasRPath(t, "../../bin/exe", gorootInstallDir)
-	AssertHasRPath(t, "../../bin/exe", filepath.Dir(gopathInstallDir))
-	// And check it runs.
-	run(t, "executable linked to GOPATH library", "../../bin/exe")
-}
-
-// The shared library contains a note listing the packages it contains in a section
-// that is not mapped into memory.
-func testPkgListNote(t *testing.T, f *elf.File, note *note) {
-	if note.section.Flags != 0 {
-		t.Errorf("package list section has flags %v, want 0", note.section.Flags)
-	}
-	if isOffsetLoaded(f, note.section.Offset) {
-		t.Errorf("package list section contained in PT_LOAD segment")
-	}
-	if note.desc != "testshared/depBase\n" {
-		t.Errorf("incorrect package list %q, want %q", note.desc, "testshared/depBase\n")
-	}
-}
-
-// The shared library contains a note containing the ABI hash that is mapped into
-// memory and there is a local symbol called go.link.abihashbytes that points 16
-// bytes into it.
-func testABIHashNote(t *testing.T, f *elf.File, note *note) {
-	if note.section.Flags != elf.SHF_ALLOC {
-		t.Errorf("abi hash section has flags %v, want SHF_ALLOC", note.section.Flags)
-	}
-	if !isOffsetLoaded(f, note.section.Offset) {
-		t.Errorf("abihash section not contained in PT_LOAD segment")
-	}
-	var hashbytes elf.Symbol
-	symbols, err := f.Symbols()
-	if err != nil {
-		t.Errorf("error reading symbols %v", err)
-		return
-	}
-	for _, sym := range symbols {
-		if sym.Name == "go.link.abihashbytes" {
-			hashbytes = sym
-		}
-	}
-	if hashbytes.Name == "" {
-		t.Errorf("no symbol called go.link.abihashbytes")
-		return
-	}
-	if elf.ST_BIND(hashbytes.Info) != elf.STB_LOCAL {
-		t.Errorf("%s has incorrect binding %v, want STB_LOCAL", hashbytes.Name, elf.ST_BIND(hashbytes.Info))
-	}
-	if f.Sections[hashbytes.Section] != note.section {
-		t.Errorf("%s has incorrect section %v, want %s", hashbytes.Name, f.Sections[hashbytes.Section].Name, note.section.Name)
-	}
-	if hashbytes.Value-note.section.Addr != 16 {
-		t.Errorf("%s has incorrect offset into section %d, want 16", hashbytes.Name, hashbytes.Value-note.section.Addr)
-	}
-}
-
-// A Go shared library contains a note indicating which other Go shared libraries it
-// was linked against in an unmapped section.
-func testDepsNote(t *testing.T, f *elf.File, note *note) {
-	if note.section.Flags != 0 {
-		t.Errorf("package list section has flags %v, want 0", note.section.Flags)
-	}
-	if isOffsetLoaded(f, note.section.Offset) {
-		t.Errorf("package list section contained in PT_LOAD segment")
-	}
-	// libdepBase.so just links against the lib containing the runtime.
-	if note.desc != soname {
-		t.Errorf("incorrect dependency list %q, want %q", note.desc, soname)
-	}
-}
-
-// The shared library contains notes with defined contents; see above.
-func TestNotes(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./depBase")
-	shlib := goCmd(t, "list", "-f", "{{.Shlib}}", "-buildmode=shared", "-linkshared", "./depBase")
-	f, err := elf.Open(shlib)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer f.Close()
-	notes, err := readNotes(f)
-	if err != nil {
-		t.Fatal(err)
-	}
-	pkgListNoteFound := false
-	abiHashNoteFound := false
-	depsNoteFound := false
-	for _, note := range notes {
-		if note.name != "Go\x00\x00" {
-			continue
-		}
-		switch note.tag {
-		case 1: // ELF_NOTE_GOPKGLIST_TAG
-			if pkgListNoteFound {
-				t.Error("multiple package list notes")
-			}
-			testPkgListNote(t, f, note)
-			pkgListNoteFound = true
-		case 2: // ELF_NOTE_GOABIHASH_TAG
-			if abiHashNoteFound {
-				t.Error("multiple abi hash notes")
-			}
-			testABIHashNote(t, f, note)
-			abiHashNoteFound = true
-		case 3: // ELF_NOTE_GODEPS_TAG
-			if depsNoteFound {
-				t.Error("multiple dependency list notes")
-			}
-			testDepsNote(t, f, note)
-			depsNoteFound = true
-		}
-	}
-	if !pkgListNoteFound {
-		t.Error("package list note not found")
-	}
-	if !abiHashNoteFound {
-		t.Error("abi hash note not found")
-	}
-	if !depsNoteFound {
-		t.Error("deps note not found")
-	}
-}
-
-// Build a GOPATH package (depBase) into a shared library that links against the goroot
-// runtime, another package (dep2) that links against the first, and an
-// executable that links against dep2.
-func TestTwoGopathShlibs(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./depBase")
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./dep2")
-	goCmd(t, "install", "-linkshared", "./exe2")
-	run(t, "executable linked to GOPATH library", "../../bin/exe2")
-}
-
-func TestThreeGopathShlibs(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./depBase")
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./dep2")
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./dep3")
-	goCmd(t, "install", "-linkshared", "./exe3")
-	run(t, "executable linked to GOPATH library", "../../bin/exe3")
-}
-
-// If gccgo is not available or not new enough, call t.Skip.
-func requireGccgo(t *testing.T) {
-	t.Helper()
-
-	gccgoName := os.Getenv("GCCGO")
-	if gccgoName == "" {
-		gccgoName = "gccgo"
-	}
-	gccgoPath, err := exec.LookPath(gccgoName)
-	if err != nil {
-		t.Skip("gccgo not found")
-	}
-	cmd := exec.Command(gccgoPath, "-dumpversion")
-	output, err := cmd.CombinedOutput()
-	if err != nil {
-		t.Fatalf("%s -dumpversion failed: %v\n%s", gccgoPath, err, output)
-	}
-	if string(output) < "5" {
-		t.Skipf("gccgo too old (%s)", strings.TrimSpace(string(output)))
-	}
-
-	gomod, err := exec.Command("go", "env", "GOMOD").Output()
-	if err != nil {
-		t.Fatalf("go env GOMOD: %v", err)
-	}
-	if len(bytes.TrimSpace(gomod)) > 0 {
-		t.Skipf("gccgo not supported in module mode; see golang.org/issue/30344")
-	}
-}
-
-// Build a GOPATH package into a shared library with gccgo and an executable that
-// links against it.
-func TestGoPathShlibGccgo(t *testing.T) {
-	requireGccgo(t)
-
-	libgoRE := regexp.MustCompile("libgo.so.[0-9]+")
-
-	goCmd(t, "install", "-compiler=gccgo", "-buildmode=shared", "-linkshared", "./depBase")
-
-	// Run 'go list' after 'go install': with gccgo, we apparently don't know the
-	// shlib location until after we've installed it.
-	shlib := goCmd(t, "list", "-compiler=gccgo", "-buildmode=shared", "-linkshared", "-f", "{{.Shlib}}", "./depBase")
-
-	AssertIsLinkedToRegexp(t, shlib, libgoRE)
-	goCmd(t, "install", "-compiler=gccgo", "-linkshared", "./exe")
-	AssertIsLinkedToRegexp(t, "../../bin/exe", libgoRE)
-	AssertIsLinkedTo(t, "../../bin/exe", filepath.Base(shlib))
-	AssertHasRPath(t, "../../bin/exe", filepath.Dir(shlib))
-	// And check it runs.
-	run(t, "gccgo-built", "../../bin/exe")
-}
-
-// The gccgo version of TestTwoGopathShlibs: build a GOPATH package into a shared
-// library with gccgo, another GOPATH package that depends on the first and an
-// executable that links the second library.
-func TestTwoGopathShlibsGccgo(t *testing.T) {
-	requireGccgo(t)
-
-	libgoRE := regexp.MustCompile("libgo.so.[0-9]+")
-
-	goCmd(t, "install", "-compiler=gccgo", "-buildmode=shared", "-linkshared", "./depBase")
-	goCmd(t, "install", "-compiler=gccgo", "-buildmode=shared", "-linkshared", "./dep2")
-	goCmd(t, "install", "-compiler=gccgo", "-linkshared", "./exe2")
-
-	// Run 'go list' after 'go install': with gccgo, we apparently don't know the
-	// shlib location until after we've installed it.
-	dep2 := goCmd(t, "list", "-compiler=gccgo", "-buildmode=shared", "-linkshared", "-f", "{{.Shlib}}", "./dep2")
-	depBase := goCmd(t, "list", "-compiler=gccgo", "-buildmode=shared", "-linkshared", "-f", "{{.Shlib}}", "./depBase")
-
-	AssertIsLinkedToRegexp(t, depBase, libgoRE)
-	AssertIsLinkedToRegexp(t, dep2, libgoRE)
-	AssertIsLinkedTo(t, dep2, filepath.Base(depBase))
-	AssertIsLinkedToRegexp(t, "../../bin/exe2", libgoRE)
-	AssertIsLinkedTo(t, "../../bin/exe2", filepath.Base(dep2))
-	AssertIsLinkedTo(t, "../../bin/exe2", filepath.Base(depBase))
-
-	// And check it runs.
-	run(t, "gccgo-built", "../../bin/exe2")
-}
-
-// Testing rebuilding of shared libraries when they are stale is a bit more
-// complicated that it seems like it should be. First, we make everything "old": but
-// only a few seconds old, or it might be older than gc (or the runtime source) and
-// everything will get rebuilt. Then define a timestamp slightly newer than this
-// time, which is what we set the mtime to of a file to cause it to be seen as new,
-// and finally another slightly even newer one that we can compare files against to
-// see if they have been rebuilt.
-var oldTime = time.Now().Add(-9 * time.Second)
-var nearlyNew = time.Now().Add(-6 * time.Second)
-var stampTime = time.Now().Add(-3 * time.Second)
-
-// resetFileStamps makes "everything" (bin, src, pkg from GOPATH and the
-// test-specific parts of GOROOT) appear old.
-func resetFileStamps() {
-	chtime := func(path string, info os.FileInfo, err error) error {
-		return os.Chtimes(path, oldTime, oldTime)
-	}
-	reset := func(path string) {
-		if err := filepath.Walk(path, chtime); err != nil {
-			log.Panicf("resetFileStamps failed: %v", err)
-		}
-
-	}
-	reset("../../bin")
-	reset("../../pkg")
-	reset("../../src")
-	reset(gorootInstallDir)
-}
-
-// touch changes path and returns a function that changes it back.
-// It also sets the time of the file, so that we can see if it is rewritten.
-func touch(t *testing.T, path string) (cleanup func()) {
-	t.Helper()
-	data, err := os.ReadFile(path)
-	if err != nil {
-		t.Fatal(err)
-	}
-	old := make([]byte, len(data))
-	copy(old, data)
-	if bytes.HasPrefix(data, []byte("!<arch>\n")) {
-		// Change last digit of build ID.
-		// (Content ID in the new content-based build IDs.)
-		const marker = `build id "`
-		i := bytes.Index(data, []byte(marker))
-		if i < 0 {
-			t.Fatal("cannot find build id in archive")
-		}
-		j := bytes.IndexByte(data[i+len(marker):], '"')
-		if j < 0 {
-			t.Fatal("cannot find build id in archive")
-		}
-		i += len(marker) + j - 1
-		if data[i] == 'a' {
-			data[i] = 'b'
-		} else {
-			data[i] = 'a'
-		}
-	} else {
-		// assume it's a text file
-		data = append(data, '\n')
-	}
-
-	// If the file is still a symlink from an overlay, delete it so that we will
-	// replace it with a regular file instead of overwriting the symlinked one.
-	fi, err := os.Lstat(path)
-	if err == nil && !fi.Mode().IsRegular() {
-		fi, err = os.Stat(path)
-		if err := os.Remove(path); err != nil {
-			t.Fatal(err)
-		}
-	}
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	// If we're replacing a symlink to a read-only file, make the new file
-	// user-writable.
-	perm := fi.Mode().Perm() | 0200
-
-	if err := os.WriteFile(path, data, perm); err != nil {
-		t.Fatal(err)
-	}
-	if err := os.Chtimes(path, nearlyNew, nearlyNew); err != nil {
-		t.Fatal(err)
-	}
-	return func() {
-		if err := os.WriteFile(path, old, perm); err != nil {
-			t.Fatal(err)
-		}
-	}
-}
-
-// isNew returns if the path is newer than the time stamp used by touch.
-func isNew(t *testing.T, path string) bool {
-	t.Helper()
-	fi, err := os.Stat(path)
-	if err != nil {
-		t.Fatal(err)
-	}
-	return fi.ModTime().After(stampTime)
-}
-
-// Fail unless path has been rebuilt (i.e. is newer than the time stamp used by
-// isNew)
-func AssertRebuilt(t *testing.T, msg, path string) {
-	t.Helper()
-	if !isNew(t, path) {
-		t.Errorf("%s was not rebuilt (%s)", msg, path)
-	}
-}
-
-// Fail if path has been rebuilt (i.e. is newer than the time stamp used by isNew)
-func AssertNotRebuilt(t *testing.T, msg, path string) {
-	t.Helper()
-	if isNew(t, path) {
-		t.Errorf("%s was rebuilt (%s)", msg, path)
-	}
-}
-
-func TestRebuilding(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./depBase")
-	goCmd(t, "install", "-linkshared", "./exe")
-	info := strings.Fields(goCmd(t, "list", "-buildmode=shared", "-linkshared", "-f", "{{.Target}} {{.Shlib}}", "./depBase"))
-	if len(info) != 2 {
-		t.Fatalf("go list failed to report Target and/or Shlib")
-	}
-	target := info[0]
-	shlib := info[1]
-
-	// If the source is newer than both the .a file and the .so, both are rebuilt.
-	t.Run("newsource", func(t *testing.T) {
-		resetFileStamps()
-		cleanup := touch(t, "./depBase/dep.go")
-		defer func() {
-			cleanup()
-			goCmd(t, "install", "-linkshared", "./exe")
-		}()
-		goCmd(t, "install", "-linkshared", "./exe")
-		AssertRebuilt(t, "new source", target)
-		AssertRebuilt(t, "new source", shlib)
-	})
-
-	// If the .a file is newer than the .so, the .so is rebuilt (but not the .a)
-	t.Run("newarchive", func(t *testing.T) {
-		resetFileStamps()
-		AssertNotRebuilt(t, "new .a file before build", target)
-		goCmd(t, "list", "-linkshared", "-f={{.ImportPath}} {{.Stale}} {{.StaleReason}} {{.Target}}", "./depBase")
-		AssertNotRebuilt(t, "new .a file before build", target)
-		cleanup := touch(t, target)
-		defer func() {
-			cleanup()
-			goCmd(t, "install", "-v", "-linkshared", "./exe")
-		}()
-		goCmd(t, "install", "-v", "-linkshared", "./exe")
-		AssertNotRebuilt(t, "new .a file", target)
-		AssertRebuilt(t, "new .a file", shlib)
-	})
-}
-
-func appendFile(t *testing.T, path, content string) {
-	t.Helper()
-	f, err := os.OpenFile(path, os.O_WRONLY|os.O_APPEND, 0660)
-	if err != nil {
-		t.Fatalf("os.OpenFile failed: %v", err)
-	}
-	defer func() {
-		err := f.Close()
-		if err != nil {
-			t.Fatalf("f.Close failed: %v", err)
-		}
-	}()
-	_, err = f.WriteString(content)
-	if err != nil {
-		t.Fatalf("f.WriteString failed: %v", err)
-	}
-}
-
-func createFile(t *testing.T, path, content string) {
-	t.Helper()
-	f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0644)
-	if err != nil {
-		t.Fatalf("os.OpenFile failed: %v", err)
-	}
-	_, err = f.WriteString(content)
-	if closeErr := f.Close(); err == nil {
-		err = closeErr
-	}
-	if err != nil {
-		t.Fatalf("WriteString failed: %v", err)
-	}
-}
-
-func TestABIChecking(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./depBase")
-	goCmd(t, "install", "-linkshared", "./exe")
-
-	// If we make an ABI-breaking change to depBase and rebuild libp.so but not exe,
-	// exe will abort with a complaint on startup.
-	// This assumes adding an exported function breaks ABI, which is not true in
-	// some senses but suffices for the narrow definition of ABI compatibility the
-	// toolchain uses today.
-	resetFileStamps()
-
-	createFile(t, "./depBase/break.go", "package depBase\nfunc ABIBreak() {}\n")
-	defer os.Remove("./depBase/break.go")
-
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./depBase")
-	c := exec.Command("../../bin/exe")
-	output, err := c.CombinedOutput()
-	if err == nil {
-		t.Fatal("executing exe did not fail after ABI break")
-	}
-	scanner := bufio.NewScanner(bytes.NewReader(output))
-	foundMsg := false
-	const wantPrefix = "abi mismatch detected between the executable and lib"
-	for scanner.Scan() {
-		if strings.HasPrefix(scanner.Text(), wantPrefix) {
-			foundMsg = true
-			break
-		}
-	}
-	if err = scanner.Err(); err != nil {
-		t.Errorf("scanner encountered error: %v", err)
-	}
-	if !foundMsg {
-		t.Fatalf("exe failed, but without line %q; got output:\n%s", wantPrefix, output)
-	}
-
-	// Rebuilding exe makes it work again.
-	goCmd(t, "install", "-linkshared", "./exe")
-	run(t, "rebuilt exe", "../../bin/exe")
-
-	// If we make a change which does not break ABI (such as adding an unexported
-	// function) and rebuild libdepBase.so, exe still works, even if new function
-	// is in a file by itself.
-	resetFileStamps()
-	createFile(t, "./depBase/dep2.go", "package depBase\nfunc noABIBreak() {}\n")
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./depBase")
-	run(t, "after non-ABI breaking change", "../../bin/exe")
-}
-
-// If a package 'explicit' imports a package 'implicit', building
-// 'explicit' into a shared library implicitly includes implicit in
-// the shared library. Building an executable that imports both
-// explicit and implicit builds the code from implicit into the
-// executable rather than fetching it from the shared library. The
-// link still succeeds and the executable still runs though.
-func TestImplicitInclusion(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./explicit")
-	goCmd(t, "install", "-linkshared", "./implicitcmd")
-	run(t, "running executable linked against library that contains same package as it", "../../bin/implicitcmd")
-}
-
-// Tests to make sure that the type fields of empty interfaces and itab
-// fields of nonempty interfaces are unique even across modules,
-// so that interface equality works correctly.
-func TestInterface(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./iface_a")
-	// Note: iface_i gets installed implicitly as a dependency of iface_a.
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./iface_b")
-	goCmd(t, "install", "-linkshared", "./iface")
-	run(t, "running type/itab uniqueness tester", "../../bin/iface")
-}
-
-// Access a global variable from a library.
-func TestGlobal(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./globallib")
-	goCmd(t, "install", "-linkshared", "./global")
-	run(t, "global executable", "../../bin/global")
-	AssertIsLinkedTo(t, "../../bin/global", soname)
-	AssertHasRPath(t, "../../bin/global", gorootInstallDir)
-}
-
-// Run a test using -linkshared of an installed shared package.
-// Issue 26400.
-func TestTestInstalledShared(t *testing.T) {
-	goCmd(t, "test", "-linkshared", "-test.short", "sync/atomic")
-}
-
-// Test generated pointer method with -linkshared.
-// Issue 25065.
-func TestGeneratedMethod(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./issue25065")
-}
-
-// Test use of shared library struct with generated hash function.
-// Issue 30768.
-func TestGeneratedHash(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./issue30768/issue30768lib")
-	goCmd(t, "test", "-linkshared", "./issue30768")
-}
-
-// Test that packages can be added not in dependency order (here a depends on b, and a adds
-// before b). This could happen with e.g. go build -buildmode=shared std. See issue 39777.
-func TestPackageOrder(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./issue39777/a", "./issue39777/b")
-}
-
-// Test that GC data are generated correctly by the linker when it needs a type defined in
-// a shared library. See issue 39927.
-func TestGCData(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./gcdata/p")
-	goCmd(t, "build", "-linkshared", "./gcdata/main")
-	runWithEnv(t, "running gcdata/main", []string{"GODEBUG=clobberfree=1"}, "./main")
-}
-
-// Test that we don't decode type symbols from shared libraries (which has no data,
-// causing panic). See issue 44031.
-func TestIssue44031(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./issue44031/a")
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./issue44031/b")
-	goCmd(t, "run", "-linkshared", "./issue44031/main")
-}
-
-// Test that we use a variable from shared libraries (which implement an
-// interface in shared libraries.). A weak reference is used in the itab
-// in main process. It can cause unreacheble panic. See issue 47873.
-func TestIssue47873(t *testing.T) {
-	goCmd(t, "install", "-buildmode=shared", "-linkshared", "./issue47837/a")
-	goCmd(t, "run", "-linkshared", "./issue47837/main")
-}
diff --git a/misc/cgo/testshared/testdata/dep2/dep2.go b/misc/cgo/testshared/testdata/dep2/dep2.go
deleted file mode 100644
index 94f38cf5..0000000
--- a/misc/cgo/testshared/testdata/dep2/dep2.go
+++ /dev/null
@@ -1,15 +0,0 @@
-package dep2
-
-import "testshared/depBase"
-
-var W int = 1
-
-var hasProg depBase.HasProg
-
-type Dep2 struct {
-	depBase.Dep
-}
-
-func G() int {
-	return depBase.F() + 1
-}
diff --git a/misc/cgo/testshared/testdata/dep3/dep3.go b/misc/cgo/testshared/testdata/dep3/dep3.go
deleted file mode 100644
index 6b02ad2..0000000
--- a/misc/cgo/testshared/testdata/dep3/dep3.go
+++ /dev/null
@@ -1,22 +0,0 @@
-package dep3
-
-// The point of this test file is that it references a type from
-// depBase that is also referenced in dep2, but dep2 is loaded by the
-// linker before depBase (because it is earlier in the import list).
-// There was a bug in the linker where it would not correctly read out
-// the type data in this case and later crash.
-
-import (
-	"testshared/dep2"
-	"testshared/depBase"
-)
-
-type Dep3 struct {
-	dep  depBase.Dep
-	dep2 dep2.Dep2
-}
-
-func D3() int {
-	var x Dep3
-	return x.dep.X + x.dep2.X
-}
diff --git a/misc/cgo/testshared/testdata/depBase/asm.s b/misc/cgo/testshared/testdata/depBase/asm.s
deleted file mode 100644
index 0f1111f..0000000
--- a/misc/cgo/testshared/testdata/depBase/asm.s
+++ /dev/null
@@ -1,10 +0,0 @@
-// 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.
-
-// +build gc
-
-#include "textflag.h"
-
-TEXT ·ImplementedInAsm(SB),NOSPLIT,$0-0
-       RET
diff --git a/misc/cgo/testshared/testdata/depBase/dep.go b/misc/cgo/testshared/testdata/depBase/dep.go
deleted file mode 100644
index e7cc7c8..0000000
--- a/misc/cgo/testshared/testdata/depBase/dep.go
+++ /dev/null
@@ -1,37 +0,0 @@
-// Copyright 2016 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 depBase
-
-import (
-	"os"
-	"reflect"
-)
-
-var SlicePtr interface{} = &[]int{}
-
-var V int = 1
-
-var HasMask []string = []string{"hi"}
-
-type HasProg struct {
-	array [1024]*byte
-}
-
-type Dep struct {
-	X int
-}
-
-func (d *Dep) Method() int {
-	// This code below causes various go.itab.* symbols to be generated in
-	// the shared library. Similar code in ../exe/exe.go results in
-	// exercising https://golang.org/issues/17594
-	reflect.TypeOf(os.Stdout).Elem()
-	return 10
-}
-
-func F() int {
-	defer func() {}()
-	return V
-}
diff --git a/misc/cgo/testshared/testdata/depBase/gccgo.go b/misc/cgo/testshared/testdata/depBase/gccgo.go
deleted file mode 100644
index 2b02a1e..0000000
--- a/misc/cgo/testshared/testdata/depBase/gccgo.go
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright 2016 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.
-
-// +build gccgo
-
-package depBase
-
-func ImplementedInAsm() {}
diff --git a/misc/cgo/testshared/testdata/depBase/stubs.go b/misc/cgo/testshared/testdata/depBase/stubs.go
deleted file mode 100644
index c779538..0000000
--- a/misc/cgo/testshared/testdata/depBase/stubs.go
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright 2016 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.
-
-// +build gc
-
-package depBase
-
-func ImplementedInAsm()
diff --git a/misc/cgo/testshared/testdata/division/division.go b/misc/cgo/testshared/testdata/division/division.go
deleted file mode 100644
index bb5fc98..0000000
--- a/misc/cgo/testshared/testdata/division/division.go
+++ /dev/null
@@ -1,17 +0,0 @@
-// 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 main
-
-//go:noinline
-func div(x, y uint32) uint32 {
-	return x / y
-}
-
-func main() {
-	a := div(97, 11)
-	if a != 8 {
-		panic("FAIL")
-	}
-}
diff --git a/misc/cgo/testshared/testdata/exe/exe.go b/misc/cgo/testshared/testdata/exe/exe.go
deleted file mode 100644
index ee95f97..0000000
--- a/misc/cgo/testshared/testdata/exe/exe.go
+++ /dev/null
@@ -1,45 +0,0 @@
-package main
-
-import (
-	"os"
-	"reflect"
-	"runtime"
-
-	"testshared/depBase"
-)
-
-// Having a function declared in the main package triggered
-// golang.org/issue/18250
-func DeclaredInMain() {
-}
-
-type C struct {
-}
-
-func F() *C {
-	return nil
-}
-
-var slicePtr interface{} = &[]int{}
-
-func main() {
-	defer depBase.ImplementedInAsm()
-	// This code below causes various go.itab.* symbols to be generated in
-	// the executable. Similar code in ../depBase/dep.go results in
-	// exercising https://golang.org/issues/17594
-	reflect.TypeOf(os.Stdout).Elem()
-	runtime.GC()
-	depBase.V = depBase.F() + 1
-
-	var c *C
-	if reflect.TypeOf(F).Out(0) != reflect.TypeOf(c) {
-		panic("bad reflection results, see golang.org/issue/18252")
-	}
-
-	sp := reflect.New(reflect.TypeOf(slicePtr).Elem())
-	s := sp.Interface()
-
-	if reflect.TypeOf(s) != reflect.TypeOf(slicePtr) {
-		panic("bad reflection results, see golang.org/issue/18729")
-	}
-}
diff --git a/misc/cgo/testshared/testdata/exe2/exe2.go b/misc/cgo/testshared/testdata/exe2/exe2.go
deleted file mode 100644
index 433f331..0000000
--- a/misc/cgo/testshared/testdata/exe2/exe2.go
+++ /dev/null
@@ -1,8 +0,0 @@
-package main
-
-import "testshared/dep2"
-
-func main() {
-	d := &dep2.Dep2{}
-	dep2.W = dep2.G() + 1 + d.Method()
-}
diff --git a/misc/cgo/testshared/testdata/exe3/exe3.go b/misc/cgo/testshared/testdata/exe3/exe3.go
deleted file mode 100644
index 533e3a9..0000000
--- a/misc/cgo/testshared/testdata/exe3/exe3.go
+++ /dev/null
@@ -1,7 +0,0 @@
-package main
-
-import "testshared/dep3"
-
-func main() {
-	dep3.D3()
-}
diff --git a/misc/cgo/testshared/testdata/execgo/exe.go b/misc/cgo/testshared/testdata/execgo/exe.go
deleted file mode 100644
index 0427be8..0000000
--- a/misc/cgo/testshared/testdata/execgo/exe.go
+++ /dev/null
@@ -1,8 +0,0 @@
-package main
-
-/*
- */
-import "C"
-
-func main() {
-}
diff --git a/misc/cgo/testshared/testdata/explicit/explicit.go b/misc/cgo/testshared/testdata/explicit/explicit.go
deleted file mode 100644
index af969fcb..0000000
--- a/misc/cgo/testshared/testdata/explicit/explicit.go
+++ /dev/null
@@ -1,9 +0,0 @@
-package explicit
-
-import (
-	"testshared/implicit"
-)
-
-func E() int {
-	return implicit.I()
-}
diff --git a/misc/cgo/testshared/testdata/gcdata/main/main.go b/misc/cgo/testshared/testdata/gcdata/main/main.go
deleted file mode 100644
index 394862f..0000000
--- a/misc/cgo/testshared/testdata/gcdata/main/main.go
+++ /dev/null
@@ -1,37 +0,0 @@
-// 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.
-
-// Test that GC data is generated correctly for global
-// variables with types defined in a shared library.
-// See issue 39927.
-
-// This test run under GODEBUG=clobberfree=1. The check
-// *x[i] == 12345 depends on this debug mode to clobber
-// the value if the object is freed prematurely.
-
-package main
-
-import (
-	"fmt"
-	"runtime"
-	"testshared/gcdata/p"
-)
-
-var x p.T
-
-func main() {
-	for i := range x {
-		x[i] = new(int)
-		*x[i] = 12345
-	}
-	runtime.GC()
-	runtime.GC()
-	runtime.GC()
-	for i := range x {
-		if *x[i] != 12345 {
-			fmt.Printf("x[%d] == %d, want 12345\n", i, *x[i])
-			panic("FAIL")
-		}
-	}
-}
diff --git a/misc/cgo/testshared/testdata/gcdata/p/p.go b/misc/cgo/testshared/testdata/gcdata/p/p.go
deleted file mode 100644
index 1fee754..0000000
--- a/misc/cgo/testshared/testdata/gcdata/p/p.go
+++ /dev/null
@@ -1,7 +0,0 @@
-// 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 p
-
-type T [10]*int
diff --git a/misc/cgo/testshared/testdata/global/main.go b/misc/cgo/testshared/testdata/global/main.go
deleted file mode 100644
index f43e7c3..0000000
--- a/misc/cgo/testshared/testdata/global/main.go
+++ /dev/null
@@ -1,71 +0,0 @@
-// 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 main
-
-import (
-	"testshared/globallib"
-)
-
-//go:noinline
-func testLoop() {
-	for i, s := range globallib.Data {
-		if s != int64(i) {
-			panic("testLoop: mismatch")
-		}
-	}
-}
-
-//go:noinline
-func ptrData() *[1<<20 + 10]int64 {
-	return &globallib.Data
-}
-
-//go:noinline
-func testMediumOffset() {
-	for i, s := range globallib.Data[1<<16-2:] {
-		if s != int64(i)+1<<16-2 {
-			panic("testMediumOffset: index mismatch")
-		}
-	}
-
-	x := globallib.Data[1<<16-1]
-	if x != 1<<16-1 {
-		panic("testMediumOffset: direct mismatch")
-	}
-
-	y := &globallib.Data[1<<16-3]
-	if y != &ptrData()[1<<16-3] {
-		panic("testMediumOffset: address mismatch")
-	}
-}
-
-//go:noinline
-func testLargeOffset() {
-	for i, s := range globallib.Data[1<<20:] {
-		if s != int64(i)+1<<20 {
-			panic("testLargeOffset: index mismatch")
-		}
-	}
-
-	x := globallib.Data[1<<20+1]
-	if x != 1<<20+1 {
-		panic("testLargeOffset: direct mismatch")
-	}
-
-	y := &globallib.Data[1<<20+2]
-	if y != &ptrData()[1<<20+2] {
-		panic("testLargeOffset: address mismatch")
-	}
-}
-
-func main() {
-	testLoop()
-
-	// SSA rules commonly merge offsets into addresses. These
-	// tests access global data in different ways to try
-	// and exercise different SSA rules.
-	testMediumOffset()
-	testLargeOffset()
-}
diff --git a/misc/cgo/testshared/testdata/globallib/global.go b/misc/cgo/testshared/testdata/globallib/global.go
deleted file mode 100644
index b4372a2..0000000
--- a/misc/cgo/testshared/testdata/globallib/global.go
+++ /dev/null
@@ -1,17 +0,0 @@
-// 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 globallib
-
-// Data is large enough to that offsets into it do not fit into
-// 16-bit or 20-bit immediates. Ideally we'd also try and overrun
-// 32-bit immediates, but that requires the test machine to have
-// too much memory.
-var Data [1<<20 + 10]int64
-
-func init() {
-	for i := range Data {
-		Data[i] = int64(i)
-	}
-}
diff --git a/misc/cgo/testshared/testdata/iface/main.go b/misc/cgo/testshared/testdata/iface/main.go
deleted file mode 100644
index d26ebbc..0000000
--- a/misc/cgo/testshared/testdata/iface/main.go
+++ /dev/null
@@ -1,17 +0,0 @@
-// 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 main
-
-import "testshared/iface_a"
-import "testshared/iface_b"
-
-func main() {
-	if iface_a.F() != iface_b.F() {
-		panic("empty interfaces not equal")
-	}
-	if iface_a.G() != iface_b.G() {
-		panic("non-empty interfaces not equal")
-	}
-}
diff --git a/misc/cgo/testshared/testdata/iface_a/a.go b/misc/cgo/testshared/testdata/iface_a/a.go
deleted file mode 100644
index e2cef1e..0000000
--- a/misc/cgo/testshared/testdata/iface_a/a.go
+++ /dev/null
@@ -1,17 +0,0 @@
-// 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 iface_a
-
-import "testshared/iface_i"
-
-//go:noinline
-func F() interface{} {
-	return (*iface_i.T)(nil)
-}
-
-//go:noinline
-func G() iface_i.I {
-	return (*iface_i.T)(nil)
-}
diff --git a/misc/cgo/testshared/testdata/iface_b/b.go b/misc/cgo/testshared/testdata/iface_b/b.go
deleted file mode 100644
index dd3e027..0000000
--- a/misc/cgo/testshared/testdata/iface_b/b.go
+++ /dev/null
@@ -1,17 +0,0 @@
-// 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 iface_b
-
-import "testshared/iface_i"
-
-//go:noinline
-func F() interface{} {
-	return (*iface_i.T)(nil)
-}
-
-//go:noinline
-func G() iface_i.I {
-	return (*iface_i.T)(nil)
-}
diff --git a/misc/cgo/testshared/testdata/iface_i/i.go b/misc/cgo/testshared/testdata/iface_i/i.go
deleted file mode 100644
index 31c8038..0000000
--- a/misc/cgo/testshared/testdata/iface_i/i.go
+++ /dev/null
@@ -1,17 +0,0 @@
-// 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 iface_i
-
-type I interface {
-	M()
-}
-
-type T struct {
-}
-
-func (t *T) M() {
-}
-
-// *T implements I
diff --git a/misc/cgo/testshared/testdata/implicit/implicit.go b/misc/cgo/testshared/testdata/implicit/implicit.go
deleted file mode 100644
index 5360188..0000000
--- a/misc/cgo/testshared/testdata/implicit/implicit.go
+++ /dev/null
@@ -1,5 +0,0 @@
-package implicit
-
-func I() int {
-	return 42
-}
diff --git a/misc/cgo/testshared/testdata/implicitcmd/implicitcmd.go b/misc/cgo/testshared/testdata/implicitcmd/implicitcmd.go
deleted file mode 100644
index 4d42967..0000000
--- a/misc/cgo/testshared/testdata/implicitcmd/implicitcmd.go
+++ /dev/null
@@ -1,10 +0,0 @@
-package main
-
-import (
-	"testshared/explicit"
-	"testshared/implicit"
-)
-
-func main() {
-	println(implicit.I() + explicit.E())
-}
diff --git a/misc/cgo/testshared/testdata/issue25065/a.go b/misc/cgo/testshared/testdata/issue25065/a.go
deleted file mode 100644
index 979350f..0000000
--- a/misc/cgo/testshared/testdata/issue25065/a.go
+++ /dev/null
@@ -1,20 +0,0 @@
-// 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 issue25065 has a type with a method that is
-//  1) referenced in a method expression
-//  2) not called
-//  3) not converted to an interface
-//  4) is a value method but the reference is to the pointer method
-// These cases avoid the call to makefuncsym from typecheckfunc, but we
-// still need to call makefuncsym somehow or the symbol will not be defined.
-package issue25065
-
-type T int
-
-func (t T) M() {}
-
-func F() func(*T) {
-	return (*T).M
-}
diff --git a/misc/cgo/testshared/testdata/issue30768/issue30768lib/lib.go b/misc/cgo/testshared/testdata/issue30768/issue30768lib/lib.go
deleted file mode 100644
index 9e45ebe..0000000
--- a/misc/cgo/testshared/testdata/issue30768/issue30768lib/lib.go
+++ /dev/null
@@ -1,11 +0,0 @@
-// 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 issue30768lib
-
-// S is a struct that requires a generated hash function.
-type S struct {
-	A string
-	B int
-}
diff --git a/misc/cgo/testshared/testdata/issue30768/x_test.go b/misc/cgo/testshared/testdata/issue30768/x_test.go
deleted file mode 100644
index 1bbd139..0000000
--- a/misc/cgo/testshared/testdata/issue30768/x_test.go
+++ /dev/null
@@ -1,22 +0,0 @@
-// 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 issue30768_test
-
-import (
-	"testing"
-
-	"testshared/issue30768/issue30768lib"
-)
-
-type s struct {
-	s issue30768lib.S
-}
-
-func Test30768(t *testing.T) {
-	// Calling t.Log will convert S to an empty interface,
-	// which will force a reference to the generated hash function,
-	// defined in the shared library.
-	t.Log(s{})
-}
diff --git a/misc/cgo/testshared/testdata/issue39777/a/a.go b/misc/cgo/testshared/testdata/issue39777/a/a.go
deleted file mode 100644
index c7bf835..0000000
--- a/misc/cgo/testshared/testdata/issue39777/a/a.go
+++ /dev/null
@@ -1,9 +0,0 @@
-// 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 a
-
-import "testshared/issue39777/b"
-
-func F() { b.F() }
diff --git a/misc/cgo/testshared/testdata/issue39777/b/b.go b/misc/cgo/testshared/testdata/issue39777/b/b.go
deleted file mode 100644
index 4e68196..0000000
--- a/misc/cgo/testshared/testdata/issue39777/b/b.go
+++ /dev/null
@@ -1,7 +0,0 @@
-// 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 b
-
-func F() {}
diff --git a/misc/cgo/testshared/testdata/issue44031/a/a.go b/misc/cgo/testshared/testdata/issue44031/a/a.go
deleted file mode 100644
index 48827e6..0000000
--- a/misc/cgo/testshared/testdata/issue44031/a/a.go
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright 2021 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 a
-
-type ATypeWithALoooooongName interface { // a long name, so the type descriptor symbol name is mangled
-	M()
-}
diff --git a/misc/cgo/testshared/testdata/issue44031/b/b.go b/misc/cgo/testshared/testdata/issue44031/b/b.go
deleted file mode 100644
index ad3ebec..0000000
--- a/misc/cgo/testshared/testdata/issue44031/b/b.go
+++ /dev/null
@@ -1,17 +0,0 @@
-// Copyright 2021 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 b
-
-import "testshared/issue44031/a"
-
-type T int
-
-func (T) M() {}
-
-var i = a.ATypeWithALoooooongName(T(0))
-
-func F() {
-	i.M()
-}
diff --git a/misc/cgo/testshared/testdata/issue44031/main/main.go b/misc/cgo/testshared/testdata/issue44031/main/main.go
deleted file mode 100644
index 47f2e3a..0000000
--- a/misc/cgo/testshared/testdata/issue44031/main/main.go
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright 2021 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 main
-
-import "testshared/issue44031/b"
-
-type t int
-
-func (t) m() {}
-
-type i interface{ m() } // test that unexported method is correctly marked
-
-var v interface{} = t(0)
-
-func main() {
-	b.F()
-	v.(i).m()
-}
diff --git a/misc/cgo/testshared/testdata/issue47837/a/a.go b/misc/cgo/testshared/testdata/issue47837/a/a.go
deleted file mode 100644
index 68588ed..0000000
--- a/misc/cgo/testshared/testdata/issue47837/a/a.go
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright 2021 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 a
-
-type A interface {
-	M()
-}
-
-//go:noinline
-func TheFuncWithArgA(a A) {
-	a.M()
-}
-
-type ImplA struct{}
-
-//go:noinline
-func (A *ImplA) M() {}
diff --git a/misc/cgo/testshared/testdata/issue47837/main/main.go b/misc/cgo/testshared/testdata/issue47837/main/main.go
deleted file mode 100644
index 77c6f34..0000000
--- a/misc/cgo/testshared/testdata/issue47837/main/main.go
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright 2021 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 main
-
-import (
-	"testshared/issue47837/a"
-)
-
-func main() {
-	var vara a.ImplA
-	a.TheFuncWithArgA(&vara)
-}
diff --git a/misc/cgo/testshared/testdata/trivial/trivial.go b/misc/cgo/testshared/testdata/trivial/trivial.go
deleted file mode 100644
index 6ade47c..0000000
--- a/misc/cgo/testshared/testdata/trivial/trivial.go
+++ /dev/null
@@ -1,9 +0,0 @@
-package main
-
-func main() {
-	// This is enough to make sure that the executable references
-	// a type descriptor, which was the cause of
-	// https://golang.org/issue/25970.
-	c := make(chan int)
-	_ = c
-}
diff --git a/src/cmd/dist/test.go b/src/cmd/dist/test.go
index 5935011..87238cc 100644
--- a/src/cmd/dist/test.go
+++ b/src/cmd/dist/test.go
@@ -762,9 +762,6 @@
 		if t.supportedBuildmode("c-shared") {
 			t.registerHostTest("testcshared", "../misc/cgo/testcshared", "misc/cgo/testcshared", ".")
 		}
-		if t.supportedBuildmode("shared") {
-			t.registerTest("testshared", "../misc/cgo/testshared", t.goTest(), t.timeout(600), ".")
-		}
 		if t.supportedBuildmode("plugin") {
 			t.registerTest("testplugin", "../misc/cgo/testplugin", t.goTest(), t.timeout(600), ".")
 		}
@@ -1047,12 +1044,6 @@
 			return true
 		}
 		return false
-	case "shared":
-		switch pair {
-		case "linux-386", "linux-amd64", "linux-arm", "linux-arm64", "linux-ppc64le", "linux-s390x":
-			return true
-		}
-		return false
 	case "plugin":
 		// linux-arm64 is missing because it causes the external linker
 		// to crash, see https://golang.org/issue/17138
diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index 9d8c321..685ccac 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -162,9 +162,6 @@
 // 		flags has a similar effect.
 // 	-ldflags '[pattern=]arg list'
 // 		arguments to pass on each go tool link invocation.
-// 	-linkshared
-// 		build code that will be linked against shared libraries previously
-// 		created with -buildmode=shared.
 // 	-mod mode
 // 		module download mode to use: readonly, vendor, or mod.
 // 		By default, if a vendor directory is present and the go version in go.mod
@@ -778,7 +775,6 @@
 //         Name          string   // package name
 //         Doc           string   // package documentation string
 //         Target        string   // install path
-//         Shlib         string   // the shared library that contains this package (only set when -linkshared)
 //         Goroot        bool     // is this package in the Go root?
 //         Standard      bool     // is this package part of the standard Go library?
 //         Stale         bool     // would 'go install' do anything for this package?
@@ -1799,11 +1795,6 @@
 // 		non-main packages are built into .a files (the default
 // 		behavior).
 //
-// 	-buildmode=shared
-// 		Combine all the listed non-main packages into a single shared
-// 		library that will be used when building with the -linkshared
-// 		option. Packages named main are ignored.
-//
 // 	-buildmode=exe
 // 		Build the listed main packages and everything they import into
 // 		executables. Packages not named main are ignored.
diff --git a/src/cmd/go/internal/help/helpdoc.go b/src/cmd/go/internal/help/helpdoc.go
index 035235f..2bb3584 100644
--- a/src/cmd/go/internal/help/helpdoc.go
+++ b/src/cmd/go/internal/help/helpdoc.go
@@ -726,11 +726,6 @@
 		non-main packages are built into .a files (the default
 		behavior).
 
-	-buildmode=shared
-		Combine all the listed non-main packages into a single shared
-		library that will be used when building with the -linkshared
-		option. Packages named main are ignored.
-
 	-buildmode=exe
 		Build the listed main packages and everything they import into
 		executables. Packages not named main are ignored.
diff --git a/src/cmd/go/internal/list/list.go b/src/cmd/go/internal/list/list.go
index 8c85ddc..f23fbe5f 100644
--- a/src/cmd/go/internal/list/list.go
+++ b/src/cmd/go/internal/list/list.go
@@ -23,8 +23,8 @@
 	"cmd/go/internal/load"
 	"cmd/go/internal/modinfo"
 	"cmd/go/internal/modload"
-	"cmd/go/internal/work"
 	"cmd/go/internal/str"
+	"cmd/go/internal/work"
 )
 
 var CmdList = &base.Command{
@@ -56,7 +56,6 @@
         Name          string   // package name
         Doc           string   // package documentation string
         Target        string   // install path
-        Shlib         string   // the shared library that contains this package (only set when -linkshared)
         Goroot        bool     // is this package in the Go root?
         Standard      bool     // is this package part of the standard Go library?
         Stale         bool     // would 'go install' do anything for this package?
diff --git a/src/cmd/go/internal/work/build.go b/src/cmd/go/internal/work/build.go
index 9d0ad27..e39ffcb 100644
--- a/src/cmd/go/internal/work/build.go
+++ b/src/cmd/go/internal/work/build.go
@@ -116,9 +116,6 @@
 		flags has a similar effect.
 	-ldflags '[pattern=]arg list'
 		arguments to pass on each go tool link invocation.
-	-linkshared
-		build code that will be linked against shared libraries previously
-		created with -buildmode=shared.
 	-mod mode
 		module download mode to use: readonly, vendor, or mod.
 		By default, if a vendor directory is present and the go version in go.mod
diff --git a/src/cmd/go/internal/work/init.go b/src/cmd/go/internal/work/init.go
index 4dbbd2a..b2ee00d 100644
--- a/src/cmd/go/internal/work/init.go
+++ b/src/cmd/go/internal/work/init.go
@@ -246,16 +246,20 @@
 		}
 		ldBuildmode = "pie"
 	case "shared":
-		pkgsFilter = pkgsNotMain
-		if gccgo {
-			codegenArg = "-fPIC"
-		} else {
-			codegenArg = "-dynlink"
+		if cfg.Goos == "linux" {
+			switch cfg.Goarch {
+			case "386", "amd64", "arm", "arm64", "ppc64le", "s390x":
+				// -buildmode=shared was supported on these platforms at one point, but
+				// never really worked in module mode.
+				// Support was officially dropped as of Go 1.18.
+				// (See https://golang.org/issue/47788.)
+				base.Fatalf("-buildmode=shared no longer supported as of Go 1.18")
+
+				// TODO(#47788): Remove supporting code for -buildmode=shared.
+				// (For the Go 1.18 release, we will keep most of the code around but
+				// disabled to avoid merge conflicts in case we need to revert quickly.)
+			}
 		}
-		if cfg.BuildO != "" {
-			base.Fatalf("-buildmode=shared and -o not supported together")
-		}
-		ldBuildmode = "shared"
 	case "plugin":
 		pkgsFilter = oneMainPkg
 		if gccgo {
@@ -274,6 +278,15 @@
 	}
 
 	if cfg.BuildLinkshared {
+		if cfg.Goos == "linux" {
+			switch cfg.Goarch {
+			case "386", "amd64", "arm", "arm64", "ppc64le", "s390x":
+				base.Fatalf("-linkshared no longer supported as of Go 1.18")
+				// TODO(#47788): Remove supporting code for linkshared.
+				// (For the Go 1.18 release, we will keep most of the code around but
+				// disabled to avoid merge conflicts in case we need to revert quickly.)
+			}
+		}
 		if !sys.BuildModeSupported(cfg.BuildToolchainName, "shared", cfg.Goos, cfg.Goarch) {
 			base.Fatalf("-linkshared not supported on %s/%s\n", cfg.Goos, cfg.Goarch)
 		}
diff --git a/src/cmd/go/testdata/script/list_linkshared.txt b/src/cmd/go/testdata/script/list_linkshared.txt
deleted file mode 100644
index baae1e2..0000000
--- a/src/cmd/go/testdata/script/list_linkshared.txt
+++ /dev/null
@@ -1,16 +0,0 @@
-env GO111MODULE=on
-
-# golang.org/issue/35759: 'go list -linkshared'
-# panicked if invoked on a test-only package.
-
-[!buildmode:shared] skip
-
-go list -f '{{.ImportPath}}: {{.Target}} {{.Shlib}}' -linkshared .
-stdout '^example.com:  $'
-
--- go.mod --
-module example.com
-
-go 1.14
--- x.go --
-package x
diff --git a/src/cmd/internal/sys/supported.go b/src/cmd/internal/sys/supported.go
index e6c56fb..473e390 100644
--- a/src/cmd/internal/sys/supported.go
+++ b/src/cmd/internal/sys/supported.go
@@ -109,13 +109,6 @@
 		}
 		return false
 
-	case "shared":
-		switch platform {
-		case "linux/386", "linux/amd64", "linux/arm", "linux/arm64", "linux/ppc64le", "linux/s390x":
-			return true
-		}
-		return false
-
 	case "plugin":
 		switch platform {
 		case "linux/amd64", "linux/arm", "linux/arm64", "linux/386", "linux/s390x", "linux/ppc64le",