[dev.boringcrypto.go1.13] all: merge go1.13.3 into dev.boringcrypto.go1.13

Change-Id: I6153fcf6c7b933ae651228e8ce3593e861c80e49

83 files changed, 952 insertions, 1527 deletions

diff --git a/doc/devel/release.html b/doc/devel/release.html
index fc858d418b..0ac3b86334 100644
--- a/doc/devel/release.html
+++ b/doc/devel/release.html
@@ -46,6 +46,14 @@ See the <a href="https://github.com/golang/go/issues?q=milestone%3AGo1.13.2">Go
 1.13.2 milestone</a> on our issue tracker for details.
 </p>
 
+<p>
+go1.13.3 (released 2019/10/17) includes fixes to the go command,
+the toolchain, the runtime, <code>syscall</code>, <code>net</code>,
+<code>net/http</code>, and <code>crypto/ecdsa</code> packages.
+See the <a href="https://github.com/golang/go/issues?q=milestone%3AGo1.13.3">Go
+1.13.3 milestone</a> on our issue tracker for details.
+</p>
+
 <h2 id="go1.12">go1.12 (released 2019/02/25)</h2>
 
 <p>
@@ -135,6 +143,13 @@ See the <a href="https://github.com/golang/go/issues?q=milestone%3AGo1.12.11">Go
 1.12.11 milestone</a> on our issue tracker for details.
 </p>
 
+<p>
+go1.12.12 (released 2019/10/17) includes fixes to the go command,
+runtime, <code>syscall</code> and <code>net</code> packages.
+See the <a href="https://github.com/golang/go/issues?q=milestone%3AGo1.12.12">Go
+1.12.12 milestone</a> on our issue tracker for details.
+</p>
+
 <h2 id="go1.11">go1.11 (released 2018/08/24)</h2>
 
 <p>
diff --git a/doc/go1.13.html b/doc/go1.13.html
index d5809d6ad1..d4a762721f 100644
--- a/doc/go1.13.html
+++ b/doc/go1.13.html
@@ -102,7 +102,7 @@ Do not send CLs removing the interior tags from such phrases.
 
 <h2 id="ports">Ports</h2>
 
-<p>
+<p id="nacl">
   Go 1.13 is the last release that will run on Native Client (NaCl).
 </p>
 
@@ -821,7 +821,7 @@ godoc
     <p><!-- CL 154383 -->
       <a href="/pkg/net/http/#TimeoutHandler"><code>TimeoutHandler</code></a>'s
       <a href="/pkg/net/http/#ResponseWriter"><code>ResponseWriter</code></a> now implements the
-      <a href="/pkg/net/http/#Pusher"><code>Pusher</code></a> and <a href="/pkg/net/http/#Flusher"><code>Flusher</code></a> interfaces.
+      <a href="/pkg/net/http/#Pusher"><code>Pusher</code></a> interface.
     </p>
 
     <p><!-- CL 157339 -->
diff --git a/src/cmd/compile/internal/gc/noder.go b/src/cmd/compile/internal/gc/noder.go
index 93d355278e..6aca89cad9 100644
--- a/src/cmd/compile/internal/gc/noder.go
+++ b/src/cmd/compile/internal/gc/noder.go
@@ -1330,7 +1330,7 @@ func checkLangCompat(lit *syntax.BasicLit) {
 	}
 	// len(s) > 2
 	if strings.Contains(s, "_") {
-		yyerror("underscores in numeric literals only supported as of -lang=go1.13")
+		yyerrorv("go1.13", "underscores in numeric literals")
 		return
 	}
 	if s[0] != '0' {
@@ -1338,15 +1338,15 @@ func checkLangCompat(lit *syntax.BasicLit) {
 	}
 	base := s[1]
 	if base == 'b' || base == 'B' {
-		yyerror("binary literals only supported as of -lang=go1.13")
+		yyerrorv("go1.13", "binary literals")
 		return
 	}
 	if base == 'o' || base == 'O' {
-		yyerror("0o/0O-style octal literals only supported as of -lang=go1.13")
+		yyerrorv("go1.13", "0o/0O-style octal literals")
 		return
 	}
 	if lit.Kind != syntax.IntLit && (base == 'x' || base == 'X') {
-		yyerror("hexadecimal floating-point literals only supported as of -lang=go1.13")
+		yyerrorv("go1.13", "hexadecimal floating-point literals")
 	}
 }
 
diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index f3ec21c7cb..d33fd4eb6c 100644
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -154,6 +154,11 @@ func yyerrorl(pos src.XPos, format string, args ...interface{}) {
 	}
 }
 
+func yyerrorv(lang string, format string, args ...interface{}) {
+	what := fmt.Sprintf(format, args...)
+	yyerrorl(lineno, "%s requires %s or later (-lang was set to %s; check go.mod)", what, lang, flag_lang)
+}
+
 func yyerror(format string, args ...interface{}) {
 	yyerrorl(lineno, format, args...)
 }
diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index 4cb28d6100..223e5add36 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -632,7 +632,7 @@ func typecheck1(n *Node, top int) (res *Node) {
 				return n
 			}
 			if t.IsSigned() && !langSupported(1, 13) {
-				yyerror("invalid operation: %v (signed shift count type %v, only supported as of -lang=go1.13)", n, r.Type)
+				yyerrorv("go1.13", "invalid operation: %v (signed shift count type %v)", n, r.Type)
 				n.Type = nil
 				return n
 			}
diff --git a/src/cmd/cover/func.go b/src/cmd/cover/func.go
index fe64374189..988c4caebf 100644
--- a/src/cmd/cover/func.go
+++ b/src/cmd/cover/func.go
@@ -191,6 +191,10 @@ func findPkgs(profiles []*Profile) (map[string]*Pkg, error) {
 		}
 	}
 
+	if len(list) == 0 {
+		return pkgs, nil
+	}
+
 	// Note: usually run as "go tool cover" in which case $GOROOT is set,
 	// in which case runtime.GOROOT() does exactly what we want.
 	goTool := filepath.Join(runtime.GOROOT(), "bin/go")
diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index ebbead5d31..0a8935b6bc 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -1018,7 +1018,6 @@
 //         Dir      string // absolute path to cached source root directory
 //         Sum      string // checksum for path, version (as in go.sum)
 //         GoModSum string // checksum for go.mod (as in go.sum)
-//         Latest   bool   // would @latest resolve to this version?
 //     }
 //
 // See 'go help modules' for more about module queries.
diff --git a/src/cmd/go/internal/get/vcs.go b/src/cmd/go/internal/get/vcs.go
index 705bb66dbe..6ae3cffd93 100644
--- a/src/cmd/go/internal/get/vcs.go
+++ b/src/cmd/go/internal/get/vcs.go
@@ -904,7 +904,7 @@ func metaImportsForPrefix(importPrefix string, mod ModuleMode, security web.Secu
 		}
 		resp, err := web.Get(security, url)
 		if err != nil {
-			return setCache(fetchResult{url: url, err: fmt.Errorf("fetch %s: %v", resp.URL, err)})
+			return setCache(fetchResult{url: url, err: fmt.Errorf("fetching %s: %v", importPrefix, err)})
 		}
 		body := resp.Body
 		defer body.Close()
@@ -913,7 +913,7 @@ func metaImportsForPrefix(importPrefix string, mod ModuleMode, security web.Secu
 			return setCache(fetchResult{url: url, err: fmt.Errorf("parsing %s: %v", resp.URL, err)})
 		}
 		if len(imports) == 0 {
-			err = fmt.Errorf("fetch %s: no go-import meta tag", url)
+			err = fmt.Errorf("fetching %s: no go-import meta tag found in %s", importPrefix, resp.URL)
 		}
 		return setCache(fetchResult{url: url, imports: imports, err: err})
 	})
diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index 64267a4a46..07f7115e33 100644
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -1956,9 +1956,14 @@ func Packages(args []string) []*Package {
 // cannot be loaded at all.
 // The packages that fail to load will have p.Error != nil.
 func PackagesAndErrors(patterns []string) []*Package {
-	if len(patterns) > 0 {
-		for _, p := range patterns {
-			if strings.HasSuffix(p, ".go") {
+	for _, p := range patterns {
+		// Listing is only supported with all patterns referring to either:
+		// - Files that are part of the same directory.
+		// - Explicit package paths or patterns.
+		if strings.HasSuffix(p, ".go") {
+			// We need to test whether the path is an actual Go file and not a
+			// package path or pattern ending in '.go' (see golang.org/issue/34653).
+			if fi, err := os.Stat(p); err == nil && !fi.IsDir() {
 				return []*Package{GoFilesPackage(patterns)}
 			}
 		}
diff --git a/src/cmd/go/internal/load/test.go b/src/cmd/go/internal/load/test.go
index afff5deaaa..aac7d7d481 100644
--- a/src/cmd/go/internal/load/test.go
+++ b/src/cmd/go/internal/load/test.go
@@ -399,10 +399,13 @@ func recompileForTest(pmain, preal, ptest, pxtest *Package) {
 			}
 		}
 
-		// Don't compile build info from a main package. This can happen
-		// if -coverpkg patterns include main packages, since those packages
-		// are imported by pmain. See golang.org/issue/30907.
-		if p.Internal.BuildInfo != "" && p != pmain {
+		// Force main packages the test imports to be built as libraries.
+		// Normal imports of main packages are forbidden by the package loader,
+		// but this can still happen if -coverpkg patterns include main packages:
+		// covered packages are imported by pmain. Linking multiple packages
+		// compiled with '-p main' causes duplicate symbol errors.
+		// See golang.org/issue/30907, golang.org/issue/34114.
+		if p.Name == "main" && p != pmain && p != ptest {
 			split()
 		}
 	}
diff --git a/src/cmd/go/internal/modcmd/download.go b/src/cmd/go/internal/modcmd/download.go
index 60d0d5b6e2..0d432e9549 100644
--- a/src/cmd/go/internal/modcmd/download.go
+++ b/src/cmd/go/internal/modcmd/download.go
@@ -43,7 +43,6 @@ corresponding to this Go struct:
         Dir      string // absolute path to cached source root directory
         Sum      string // checksum for path, version (as in go.sum)
         GoModSum string // checksum for go.mod (as in go.sum)
-        Latest   bool   // would @latest resolve to this version?
     }
 
 See 'go help modules' for more about module queries.
@@ -66,7 +65,6 @@ type moduleJSON struct {
 	Dir      string `json:",omitempty"`
 	Sum      string `json:",omitempty"`
 	GoModSum string `json:",omitempty"`
-	Latest   bool   `json:",omitempty"`
 }
 
 func runDownload(cmd *base.Command, args []string) {
@@ -105,31 +103,6 @@ func runDownload(cmd *base.Command, args []string) {
 		work.Add(m)
 	}
 
-	latest := map[string]string{} // path → version
-	if *downloadJSON {
-		// We need to populate the Latest field, but if the main module depends on a
-		// version newer than latest — or if the version requested on the command
-		// line is itself newer than latest — that's not trivial to determine from
-		// the info returned by ListModules. Instead, we issue a separate
-		// ListModules request for "latest", which should be inexpensive relative to
-		// downloading the modules.
-		var latestArgs []string
-		for _, m := range mods {
-			if m.Error != "" {
-				continue
-			}
-			latestArgs = append(latestArgs, m.Path+"@latest")
-		}
-
-		if len(latestArgs) > 0 {
-			for _, info := range modload.ListModules(latestArgs, listU, listVersions) {
-				if info.Version != "" {
-					latest[info.Path] = info.Version
-				}
-			}
-		}
-	}
-
 	work.Do(10, func(item interface{}) {
 		m := item.(*moduleJSON)
 		var err error
@@ -160,9 +133,6 @@ func runDownload(cmd *base.Command, args []string) {
 			m.Error = err.Error()
 			return
 		}
-		if latest[m.Path] == m.Version {
-			m.Latest = true
-		}
 	})
 
 	if *downloadJSON {
diff --git a/src/cmd/go/internal/modfetch/codehost/git.go b/src/cmd/go/internal/modfetch/codehost/git.go
index d382e8ac9a..dc5add906b 100644
--- a/src/cmd/go/internal/modfetch/codehost/git.go
+++ b/src/cmd/go/internal/modfetch/codehost/git.go
@@ -241,13 +241,6 @@ func (r *gitRepo) findRef(hash string) (ref string, ok bool) {
 	return "", false
 }
 
-func unshallow(gitDir string) []string {
-	if _, err := os.Stat(filepath.Join(gitDir, "shallow")); err == nil {
-		return []string{"--unshallow"}
-	}
-	return []string{}
-}
-
 // minHashDigits is the minimum number of digits to require
 // before accepting a hex digit sequence as potentially identifying
 // a specific commit in a git repo. (Of course, users can always
@@ -397,29 +390,27 @@ func (r *gitRepo) stat(rev string) (*RevInfo, error) {
 // fetchRefsLocked requires that r.mu remain locked for the duration of the call.
 func (r *gitRepo) fetchRefsLocked() error {
 	if r.fetchLevel < fetchAll {
-		if err := r.fetchUnshallow("refs/heads/*:refs/heads/*", "refs/tags/*:refs/tags/*"); err != nil {
+		// NOTE: To work around a bug affecting Git clients up to at least 2.23.0
+		// (2019-08-16), we must first expand the set of local refs, and only then
+		// unshallow the repository as a separate fetch operation. (See
+		// golang.org/issue/34266 and
+		// https://github.com/git/git/blob/4c86140027f4a0d2caaa3ab4bd8bfc5ce3c11c8a/transport.c#L1303-L1309.)
+
+		if _, err := Run(r.dir, "git", "fetch", "-f", r.remote, "refs/heads/*:refs/heads/*", "refs/tags/*:refs/tags/*"); err != nil {
 			return err
 		}
+
+		if _, err := os.Stat(filepath.Join(r.dir, "shallow")); err == nil {
+			if _, err := Run(r.dir, "git", "fetch", "--unshallow", "-f", r.remote); err != nil {
+				return err
+			}
+		}
+
 		r.fetchLevel = fetchAll
 	}
 	return nil
 }
 
-func (r *gitRepo) fetchUnshallow(refSpecs ...string) error {
-	// To work around a protocol version 2 bug that breaks --unshallow,
-	// add -c protocol.version=0.
-	// TODO(rsc): The bug is believed to be server-side, meaning only
-	// on Google's Git servers. Once the servers are fixed, drop the
-	// protocol.version=0. See Google-internal bug b/110495752.
-	var protoFlag []string
-	unshallowFlag := unshallow(r.dir)
-	if len(unshallowFlag) > 0 {
-		protoFlag = []string{"-c", "protocol.version=0"}
-	}
-	_, err := Run(r.dir, "git", protoFlag, "fetch", unshallowFlag, "-f", r.remote, refSpecs)
-	return err
-}
-
 // statLocal returns a RevInfo describing rev in the local git repository.
 // It uses version as info.Version.
 func (r *gitRepo) statLocal(version, rev string) (*RevInfo, error) {
@@ -539,39 +530,10 @@ func (r *gitRepo) ReadFileRevs(revs []string, file string, maxSize int64) (map[s
 	}
 	defer unlock()
 
-	var refs []string
-	var protoFlag []string
-	var unshallowFlag []string
-	for _, tag := range redo {
-		refs = append(refs, "refs/tags/"+tag+":refs/tags/"+tag)
-	}
-	if len(refs) > 1 {
-		unshallowFlag = unshallow(r.dir)
-		if len(unshallowFlag) > 0 {
-			// To work around a protocol version 2 bug that breaks --unshallow,
-			// add -c protocol.version=0.
-			// TODO(rsc): The bug is believed to be server-side, meaning only
-			// on Google's Git servers. Once the servers are fixed, drop the
-			// protocol.version=0. See Google-internal bug b/110495752.
-			protoFlag = []string{"-c", "protocol.version=0"}
-		}
-	}
-	if _, err := Run(r.dir, "git", protoFlag, "fetch", unshallowFlag, "-f", r.remote, refs); err != nil {
+	if err := r.fetchRefsLocked(); err != nil {
 		return nil, err
 	}
 
-	// TODO(bcmills): after the 1.11 freeze, replace the block above with:
-	//	if r.fetchLevel <= fetchSome {
-	//		r.fetchLevel = fetchSome
-	//		var refs []string
-	//		for _, tag := range redo {
-	//			refs = append(refs, "refs/tags/"+tag+":refs/tags/"+tag)
-	//		}
-	//		if _, err := Run(r.dir, "git", "fetch", "--update-shallow", "-f", r.remote, refs); err != nil {
-	//			return nil, err
-	//		}
-	//	}
-
 	if _, err := r.readFileRevs(redo, file, files); err != nil {
 		return nil, err
 	}
diff --git a/src/cmd/go/internal/modfetch/coderepo_test.go b/src/cmd/go/internal/modfetch/coderepo_test.go
index 1f2b95bd23..663324b3dd 100644
--- a/src/cmd/go/internal/modfetch/coderepo_test.go
+++ b/src/cmd/go/internal/modfetch/coderepo_test.go
@@ -338,10 +338,10 @@ var codeRepoTests = []codeRepoTest{
 		vcs:     "git",
 		path:    "gopkg.in/yaml.v2",
 		rev:     "v2",
-		version: "v2.2.3-0.20190319135612-7b8349ac747c",
-		name:    "7b8349ac747c6a24702b762d2c4fd9266cf4f1d6",
-		short:   "7b8349ac747c",
-		time:    time.Date(2019, 03, 19, 13, 56, 12, 0, time.UTC),
+		version: "v2.2.5-0.20191002202810-970885f01c8b",
+		name:    "970885f01c8bc1fecb7ab1c8ce8e7609bda45530",
+		short:   "970885f01c8b",
+		time:    time.Date(2019, 10, 2, 20, 28, 10, 0, time.UTC),
 		gomod:   "module \"gopkg.in/yaml.v2\"\n\nrequire (\n\t\"gopkg.in/check.v1\" v0.0.0-20161208181325-20d25e280405\n)\n",
 	},
 	{
diff --git a/src/cmd/go/internal/modload/import_test.go b/src/cmd/go/internal/modload/import_test.go
index c6ade5d17f..c58892e2ab 100644
--- a/src/cmd/go/internal/modload/import_test.go
+++ b/src/cmd/go/internal/modload/import_test.go
@@ -21,7 +21,7 @@ var importTests = []struct {
 	},
 	{
 		path: "golang.org/x/net",
-		err:  "module golang.org/x/net@.* found, but does not contain package golang.org/x/net",
+		err:  `module golang.org/x/net@.* found \(v0.0.0-.*\), but does not contain package golang.org/x/net`,
 	},
 	{
 		path: "golang.org/x/text",
diff --git a/src/cmd/go/internal/modload/load.go b/src/cmd/go/internal/modload/load.go
index b50a084166..92e76a9246 100644
--- a/src/cmd/go/internal/modload/load.go
+++ b/src/cmd/go/internal/modload/load.go
@@ -1205,6 +1205,11 @@ func (*mvsReqs) next(m module.Version) (module.Version, error) {
 	return module.Version{Path: m.Path, Version: "none"}, nil
 }
 
+// fetch downloads the given module (or its replacement)
+// and returns its location.
+//
+// The isLocal return value reports whether the replacement,
+// if any, is local to the filesystem.
 func fetch(mod module.Version) (dir string, isLocal bool, err error) {
 	if mod == Target {
 		return ModRoot(), true, nil
diff --git a/src/cmd/go/internal/modload/query.go b/src/cmd/go/internal/modload/query.go
index 602bf47275..75c18f25cc 100644
--- a/src/cmd/go/internal/modload/query.go
+++ b/src/cmd/go/internal/modload/query.go
@@ -381,9 +381,10 @@ func QueryPattern(pattern, query string, allowed func(module.Version) bool) ([]Q
 			r.Packages = match(r.Mod, root, isLocal)
 			if len(r.Packages) == 0 {
 				return r, &PackageNotInModuleError{
-					Mod:     r.Mod,
-					Query:   query,
-					Pattern: pattern,
+					Mod:         r.Mod,
+					Replacement: Replacement(r.Mod),
+					Query:       query,
+					Pattern:     pattern,
 				}
 			}
 			return r, nil
@@ -471,7 +472,17 @@ func queryPrefixModules(candidateModules []string, queryModule func(path string)
 					notExistErr = rErr
 				}
 			} else if err == nil {
-				err = r.err
+				if len(found) > 0 || noPackage != nil {
+					// golang.org/issue/34094: If we have already found a module that
+					// could potentially contain the target package, ignore unclassified
+					// errors for modules with shorter paths.
+
+					// golang.org/issue/34383 is a special case of this: if we have
+					// already found example.com/foo/v2@v2.0.0 with a matching go.mod
+					// file, ignore the error from example.com/foo@v2.0.0.
+				} else {
+					err = r.err
+				}
 			}
 		}
 	}
@@ -526,21 +537,32 @@ func (e *NoMatchingVersionError) Error() string {
 // code for the versions it knows about, and thus did not have the opportunity
 // to return a non-400 status code to suppress fallback.
 type PackageNotInModuleError struct {
-	Mod     module.Version
-	Query   string
-	Pattern string
+	Mod         module.Version
+	Replacement module.Version
+	Query       string
+	Pattern     string
 }
 
 func (e *PackageNotInModuleError) Error() string {
 	found := ""
-	if e.Query != e.Mod.Version {
+	if r := e.Replacement; r.Path != "" {
+		replacement := r.Path
+		if r.Version != "" {
+			replacement = fmt.Sprintf("%s@%s", r.Path, r.Version)
+		}
+		if e.Query == e.Mod.Version {
+			found = fmt.Sprintf(" (replaced by %s)", replacement)
+		} else {
+			found = fmt.Sprintf(" (%s, replaced by %s)", e.Mod.Version, replacement)
+		}
+	} else if e.Query != e.Mod.Version {
 		found = fmt.Sprintf(" (%s)", e.Mod.Version)
 	}
 
 	if strings.Contains(e.Pattern, "...") {
-		return fmt.Sprintf("module %s@%s%s found, but does not contain packages matching %s", e.Mod.Path, e.Query, found, e.Pattern)
+		return fmt.Sprintf("module %s@%s found%s, but does not contain packages matching %s", e.Mod.Path, e.Query, found, e.Pattern)
 	}
-	return fmt.Sprintf("module %s@%s%s found, but does not contain package %s", e.Mod.Path, e.Query, found, e.Pattern)
+	return fmt.Sprintf("module %s@%s found%s, but does not contain package %s", e.Mod.Path, e.Query, found, e.Pattern)
 }
 
 // ModuleHasRootPackage returns whether module m contains a package m.Path.
diff --git a/src/cmd/go/internal/search/search.go b/src/cmd/go/internal/search/search.go
index 0167c8d755..d794287583 100644
--- a/src/cmd/go/internal/search/search.go
+++ b/src/cmd/go/internal/search/search.go
@@ -363,30 +363,40 @@ func ImportPathsQuiet(patterns []string) []*Match {
 
 // CleanPatterns returns the patterns to use for the given
 // command line. It canonicalizes the patterns but does not
-// evaluate any matches.
+// evaluate any matches. It preserves text after '@' for commands
+// that accept versions.
 func CleanPatterns(patterns []string) []string {
 	if len(patterns) == 0 {
 		return []string{"."}
 	}
 	var out []string
 	for _, a := range patterns {
+		var p, v string
+		if i := strings.IndexByte(a, '@'); i < 0 {
+			p = a
+		} else {
+			p = a[:i]
+			v = a[i:]
+		}
+
 		// Arguments are supposed to be import paths, but
 		// as a courtesy to Windows developers, rewrite \ to /
 		// in command-line arguments. Handles .\... and so on.
 		if filepath.Separator == '\\' {
-			a = strings.ReplaceAll(a, `\`, `/`)
+			p = strings.ReplaceAll(p, `\`, `/`)
 		}
 
 		// Put argument in canonical form, but preserve leading ./.
-		if strings.HasPrefix(a, "./") {
-			a = "./" + path.Clean(a)
-			if a == "./." {
-				a = "."
+		if strings.HasPrefix(p, "./") {
+			p = "./" + path.Clean(p)
+			if p == "./." {
+				p = "."
 			}
 		} else {
-			a = path.Clean(a)
+			p = path.Clean(p)
 		}
-		out = append(out, a)
+
+		out = append(out, p+v)
 	}
 	return out
 }
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index 95000011d8..8141e31c99 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -572,8 +572,9 @@ func runTest(cmd *base.Command, args []string) {
 	}
 
 	// Pass timeout to tests if it exists.
+	// Prepend rather than appending so that it appears before positional arguments.
 	if testActualTimeout > 0 {
-		testArgs = append(testArgs, "-test.timeout="+testActualTimeout.String())
+		testArgs = append([]string{"-test.timeout=" + testActualTimeout.String()}, testArgs...)
 	}
 
 	// show passing test output (after buffering) with -v flag.
diff --git a/src/cmd/go/internal/work/exec.go b/src/cmd/go/internal/work/exec.go
index b68f902853..7dd9a90c18 100644
--- a/src/cmd/go/internal/work/exec.go
+++ b/src/cmd/go/internal/work/exec.go
@@ -200,12 +200,12 @@ func (b *Builder) buildActionID(a *Action) cache.ActionID {
 	// same compiler settings and can reuse each other's results.
 	// If not, the reason is already recorded in buildGcflags.
 	fmt.Fprintf(h, "compile\n")
+	// Only include the package directory if it may affect the output.
+	// We trim workspace paths for all packages when -trimpath is set.
 	// The compiler hides the exact value of $GOROOT
-	// when building things in GOROOT,
-	// but it does not hide the exact value of $GOPATH.
-	// Include the full dir in that case.
+	// when building things in GOROOT.
 	// Assume b.WorkDir is being trimmed properly.
-	if !p.Goroot && !strings.HasPrefix(p.Dir, b.WorkDir) {
+	if !p.Goroot && !cfg.BuildTrimpath && !strings.HasPrefix(p.Dir, b.WorkDir) {
 		fmt.Fprintf(h, "dir %s\n", p.Dir)
 	}
 	fmt.Fprintf(h, "goos %s goarch %s\n", cfg.Goos, cfg.Goarch)
@@ -1030,7 +1030,7 @@ func (b *Builder) vet(a *Action) error {
 	// dependency tree turn on *more* analysis, as here.
 	// (The unsafeptr check does not write any facts for use by
 	// later vet runs.)
-	if a.Package.Goroot && !VetExplicit {
+	if a.Package.Goroot && !VetExplicit && VetTool == "" {
 		// Note that $GOROOT/src/buildall.bash
 		// does the same for the misc-compile trybots
 		// and should be updated if these flags are
diff --git a/src/cmd/go/script_test.go b/src/cmd/go/script_test.go
index 4dcb4b4e0d..5e50dd14c7 100644
--- a/src/cmd/go/script_test.go
+++ b/src/cmd/go/script_test.go
@@ -441,10 +441,15 @@ func (ts *testScript) cmdCmp(neg bool, args []string) {
 		// It would be strange to say "this file can have any content except this precise byte sequence".
 		ts.fatalf("unsupported: ! cmp")
 	}
+	quiet := false
+	if len(args) > 0 && args[0] == "-q" {
+		quiet = true
+		args = args[1:]
+	}
 	if len(args) != 2 {
 		ts.fatalf("usage: cmp file1 file2")
 	}
-	ts.doCmdCmp(args, false)
+	ts.doCmdCmp(args, false, quiet)
 }
 
 // cmpenv compares two files with environment variable substitution.
@@ -452,13 +457,18 @@ func (ts *testScript) cmdCmpenv(neg bool, args []string) {
 	if neg {
 		ts.fatalf("unsupported: ! cmpenv")
 	}
+	quiet := false
+	if len(args) > 0 && args[0] == "-q" {
+		quiet = true
+		args = args[1:]
+	}
 	if len(args) != 2 {
 		ts.fatalf("usage: cmpenv file1 file2")
 	}
-	ts.doCmdCmp(args, true)
+	ts.doCmdCmp(args, true, quiet)
 }
 
-func (ts *testScript) doCmdCmp(args []string, env bool) {
+func (ts *testScript) doCmdCmp(args []string, env, quiet bool) {
 	name1, name2 := args[0], args[1]
 	var text1, text2 string
 	if name1 == "stdout" {
@@ -484,7 +494,9 @@ func (ts *testScript) doCmdCmp(args []string, env bool) {
 		return
 	}
 
-	fmt.Fprintf(&ts.log, "[diff -%s +%s]\n%s\n", name1, name2, diff(text1, text2))
+	if !quiet {
+		fmt.Fprintf(&ts.log, "[diff -%s +%s]\n%s\n", name1, name2, diff(text1, text2))
+	}
 	ts.fatalf("%s and %s differ", name1, name2)
 }
 
diff --git a/src/cmd/go/testdata/mod/example.com_dotgo.go_v1.0.0.txt b/src/cmd/go/testdata/mod/example.com_dotgo.go_v1.0.0.txt
new file mode 100644
index 0000000000..4f7f4d7dd2
--- /dev/null
+++ b/src/cmd/go/testdata/mod/example.com_dotgo.go_v1.0.0.txt
@@ -0,0 +1,16 @@
+This module's path ends with ".go".
+Based on github.com/nats-io/nats.go.
+Used in regression tests for golang.org/issue/32483.
+
+-- .mod --
+module example.com/dotgo.go
+
+go 1.13
+-- .info --
+{"Version":"v1.0.0"}
+-- go.mod --
+module example.com/dotgo.go
+
+go 1.13
+-- dotgo.go --
+package dotgo
diff --git a/src/cmd/go/testdata/script/build_trimpath.txt b/src/cmd/go/testdata/script/build_trimpath.txt
index f785b0cb9e..668f75599e 100644
--- a/src/cmd/go/testdata/script/build_trimpath.txt
+++ b/src/cmd/go/testdata/script/build_trimpath.txt
@@ -1,21 +1,44 @@
 [short] skip
 
 env -r GOROOT_REGEXP=$GOROOT
-env -r WORK_REGEXP=$WORK
+env -r WORK_REGEXP='$WORK'  # don't expand $WORK; grep replaces $WORK in text before matching.
 env GOROOT GOROOT_REGEXP WORK WORK_REGEXP
 
+# A binary built without -trimpath should contain the current workspace
+# and GOROOT for debugging and stack traces.
+cd a
+go build -o hello.exe hello.go
+grep -q $WORK_REGEXP hello.exe
+grep -q $GOROOT_REGEXP hello.exe
+
+# A binary built with -trimpath should not contain the current workspace
+# or GOROOT.
 go build -trimpath -o hello.exe hello.go
 ! grep -q $GOROOT_REGEXP hello.exe
 ! grep -q $WORK_REGEXP hello.exe
+cd ..
 
+# A binary from an external module built with -trimpath should not contain
+# the current workspace or GOROOT.
 env GO111MODULE=on
 go build -trimpath -o fortune.exe rsc.io/fortune
 ! grep -q $GOROOT_REGEXP fortune.exe
 ! grep -q $WORK_REGEXP fortune.exe
 
--- hello.go --
+# Two binaries built from identical packages in different directories
+# should be identical.
+mkdir b
+cp a/go.mod a/hello.go b
+cd a
+go build -trimpath -o ../a.exe .
+cd ../b
+go build -trimpath -o ../b.exe .
+cd ..
+cmp -q a.exe b.exe
+
+-- a/hello.go --
 package main
 func main() { println("hello") }
 
--- go.mod --
+-- a/go.mod --
 module m
diff --git a/src/cmd/go/testdata/script/cover_mod_empty.txt b/src/cmd/go/testdata/script/cover_mod_empty.txt
new file mode 100644
index 0000000000..3c45243edb
--- /dev/null
+++ b/src/cmd/go/testdata/script/cover_mod_empty.txt
@@ -0,0 +1,9 @@
+go tool cover -func=cover.out
+stdout total.*statements.*0.0%
+
+go mod init golang.org/issue/33855
+
+go tool cover -func=cover.out
+stdout total.*statements.*0.0%
+
+-- cover.out --
diff --git a/src/cmd/go/testdata/script/cover_pkgall_multiple_mains.txt b/src/cmd/go/testdata/script/cover_pkgall_multiple_mains.txt
index ab7cd66949..f21cd8b3a8 100644
--- a/src/cmd/go/testdata/script/cover_pkgall_multiple_mains.txt
+++ b/src/cmd/go/testdata/script/cover_pkgall_multiple_mains.txt
@@ -1,29 +1,32 @@
 # This test checks that multiple main packages can be tested
 # with -coverpkg=all without duplicate symbol errors.
-# Verifies golang.org/issue/30374.
-
-env GO111MODULE=on
+# Verifies golang.org/issue/30374, golang.org/issue/34114.
 
 [short] skip
+cd $GOPATH/src/example.com/cov
+
+env GO111MODULE=on
+go test -coverpkg=all ./...
 
+env GO111MODULE=off
 go test -coverpkg=all ./...
 
--- go.mod --
+-- $GOPATH/src/example.com/cov/go.mod --
 module example.com/cov
 
--- mainonly/mainonly.go --
+-- $GOPATH/src/example.com/cov/mainonly/mainonly.go --
 package main
 
 func main() {}
 
--- mainwithtest/mainwithtest.go --
+-- $GOPATH/src/example.com/cov/mainwithtest/mainwithtest.go --
 package main
 
 func main() {}
 
 func Foo() {}
 
--- mainwithtest/mainwithtest_test.go --
+-- $GOPATH/src/example.com/cov/mainwithtest/mainwithtest_test.go --
 package main
 
 import "testing"
@@ -32,10 +35,10 @@ func TestFoo(t *testing.T) {
   Foo()
 }
 
--- xtest/x.go --
+-- $GOPATH/src/example.com/cov/xtest/x.go --
 package x
 
--- xtest/x_test.go --
+-- $GOPATH/src/example.com/cov/xtest/x_test.go --
 package x_test
 
 import "testing"
diff --git a/src/cmd/go/testdata/script/get_insecure_redirect.txt b/src/cmd/go/testdata/script/get_insecure_redirect.txt
index a83b17672d..0478d1f75d 100644
--- a/src/cmd/go/testdata/script/get_insecure_redirect.txt
+++ b/src/cmd/go/testdata/script/get_insecure_redirect.txt
@@ -1,11 +1,10 @@
 # golang.org/issue/29591: 'go get' was following plain-HTTP redirects even without -insecure.
+# golang.org/issue/34049: 'go get' would panic in case of an insecure redirect in GOPATH mode
 
 [!net] skip
 [!exec:git] skip
 
-env GO111MODULE=on
-env GOPROXY=direct
-env GOSUMDB=off
+env GO111MODULE=off
 
 ! go get -d vcs-test.golang.org/insecure/go/insecure
 stderr 'redirected .* to insecure URL'
diff --git a/src/cmd/go/testdata/script/list_ambiguous_path.txt b/src/cmd/go/testdata/script/list_ambiguous_path.txt
new file mode 100644
index 0000000000..9f1aa37be8
--- /dev/null
+++ b/src/cmd/go/testdata/script/list_ambiguous_path.txt
@@ -0,0 +1,37 @@
+# Ensures that we can correctly list package patterns ending in '.go'.
+# See golang.org/issue/34653.
+
+# A single pattern for a package ending in '.go'.
+go list ./foo.go
+stdout '^test/foo.go$'
+
+# Multiple patterns for packages including one ending in '.go'.
+go list ./bar ./foo.go
+stdout '^test/bar$'
+stdout '^test/foo.go$'
+
+# A single pattern for a Go file.
+go list ./a.go
+stdout '^command-line-arguments$'
+
+# A single typo-ed pattern for a Go file. This should
+# treat the wrong pattern as if it were a package.
+! go list ./foo.go/b.go
+stderr 'package ./foo.go/b.go: cannot find package "."'
+
+# Multiple patterns for Go files with a typo. This should
+# treat the wrong pattern as if it were a non-existint file.
+! go list ./foo.go/a.go ./foo.go/b.go
+[windows] stderr './foo.go/b.go: The system cannot find the file specified'
+[!windows] stderr './foo.go/b.go: no such file or directory'
+
+-- a.go --
+package main
+-- bar/a.go --
+package bar
+-- foo.go/a.go --
+package foo.go
+-- go.mod --
+module "test"
+
+go 1.13
diff --git a/src/cmd/go/testdata/script/list_split_main.txt b/src/cmd/go/testdata/script/list_split_main.txt
new file mode 100644
index 0000000000..74e7d5d74c
--- /dev/null
+++ b/src/cmd/go/testdata/script/list_split_main.txt
@@ -0,0 +1,25 @@
+# This test checks that a "main" package with an external test package
+# is recompiled only once.
+# Verifies golang.org/issue/34321.
+
+env GO111MODULE=off
+
+go list -e -test -deps -f '{{if not .Standard}}{{.ImportPath}}{{end}}' pkg
+cmp stdout want
+
+-- $GOPATH/src/pkg/pkg.go --
+package main
+
+func main() {}
+
+-- $GOPATH/src/pkg/pkg_test.go --
+package main
+
+import "testing"
+
+func Test(t *testing.T) {}
+
+-- want --
+pkg
+pkg [pkg.test]
+pkg.test
diff --git a/src/cmd/go/testdata/script/mod_download.txt b/src/cmd/go/testdata/script/mod_download.txt
index 9eb3140c33..0777913786 100644
--- a/src/cmd/go/testdata/script/mod_download.txt
+++ b/src/cmd/go/testdata/script/mod_download.txt
@@ -17,7 +17,6 @@ stderr 'this.domain.is.invalid'
 stdout '"Error": ".*this.domain.is.invalid.*"'
 
 # download -json with version should print JSON
-# and download the .info file for the 'latest' version.
 go mod download -json 'rsc.io/quote@<=v1.5.0'
 stdout '^\t"Path": "rsc.io/quote"'
 stdout '^\t"Version": "v1.5.0"'
@@ -28,14 +27,13 @@ stdout '^\t"Sum": "h1:6fJa6E\+wGadANKkUMlZ0DhXFpoKlslOQDCo259XtdIE="'  # hash of
 stdout '^\t"GoModSum": "h1:LzX7hefJvL54yjefDEDHNONDjII0t9xZLPXsUe\+TKr0="'
 ! stdout '"Error"'
 
-exists $GOPATH/pkg/mod/cache/download/rsc.io/quote/@v/v1.5.2.info
-
 # download queries above should not have added to go.mod.
 go list -m all
 ! stdout rsc.io
 
 # add to go.mod so we can test non-query downloads
 go mod edit -require rsc.io/quote@v1.5.2
+! exists $GOPATH/pkg/mod/cache/download/rsc.io/quote/@v/v1.5.2.info
 ! exists $GOPATH/pkg/mod/cache/download/rsc.io/quote/@v/v1.5.2.mod
 ! exists $GOPATH/pkg/mod/cache/download/rsc.io/quote/@v/v1.5.2.zip
 
diff --git a/src/cmd/go/testdata/script/mod_download_latest.txt b/src/cmd/go/testdata/script/mod_download_latest.txt
deleted file mode 100644
index 60d860e4da..0000000000
--- a/src/cmd/go/testdata/script/mod_download_latest.txt
+++ /dev/null
@@ -1,20 +0,0 @@
-env GO111MODULE=on
-
-# If the module is the latest version of itself,
-# the Latest field should be set.
-go mod download -json rsc.io/quote@v1.5.2
-stdout '"Latest":\s*true'
-
-# If the module is older than latest, the field should be unset.
-go mod download -json rsc.io/quote@v1.5.1
-! stdout '"Latest":'
-
-# If the module is newer than "latest", the field should be unset...
-go mod download -json rsc.io/quote@v1.5.3-pre1
-! stdout '"Latest":'
-
-# ...even if that version is also what is required by the main module.
-go mod init example.com
-go mod edit -require rsc.io/quote@v1.5.3-pre1
-go mod download -json rsc.io/quote@v1.5.3-pre1
-! stdout '"Latest":'
diff --git a/src/cmd/go/testdata/script/mod_get_direct.txt b/src/cmd/go/testdata/script/mod_get_direct.txt
new file mode 100644
index 0000000000..42ccbcd38a
--- /dev/null
+++ b/src/cmd/go/testdata/script/mod_get_direct.txt
@@ -0,0 +1,20 @@
+# Regression test for golang.org/issue/34092: with an empty module cache,
+# 'GOPROXY=direct go get golang.org/x/tools/gopls@master' did not correctly
+# resolve the pseudo-version for its dependency on golang.org/x/tools.
+
+[short] skip
+[!net] skip
+[!exec:git] skip
+
+env GO111MODULE=on
+env GOPROXY=direct
+env GOSUMDB=off
+
+go list -m cloud.google.com/go@master
+! stdout 'v0.0.0-'
+
+-- go.mod --
+module example.com
+
+go 1.14
+-- go.sum --
diff --git a/src/cmd/go/testdata/script/mod_get_insecure_redirect.txt b/src/cmd/go/testdata/script/mod_get_insecure_redirect.txt
new file mode 100644
index 0000000000..a83b17672d
--- /dev/null
+++ b/src/cmd/go/testdata/script/mod_get_insecure_redirect.txt
@@ -0,0 +1,13 @@
+# golang.org/issue/29591: 'go get' was following plain-HTTP redirects even without -insecure.
+
+[!net] skip
+[!exec:git] skip
+
+env GO111MODULE=on
+env GOPROXY=direct
+env GOSUMDB=off
+
+! go get -d vcs-test.golang.org/insecure/go/insecure
+stderr 'redirected .* to insecure URL'
+
+go get -d -insecure vcs-test.golang.org/insecure/go/insecure
diff --git a/src/cmd/go/testdata/script/mod_get_major.txt b/src/cmd/go/testdata/script/mod_get_major.txt
new file mode 100644
index 0000000000..367ede9ded
--- /dev/null
+++ b/src/cmd/go/testdata/script/mod_get_major.txt
@@ -0,0 +1,23 @@
+[!net] skip
+[!exec:git] skip
+
+env GO111MODULE=on
+env GOPROXY=direct
+env GOSUMDB=off
+
+# golang.org/issue/34383: if a module path ends in a major-version suffix,
+# ensure that 'direct' mode can resolve the package to a module.
+
+go get -d vcs-test.golang.org/git/v3pkg.git/v3@v3.0.0
+
+go list -m vcs-test.golang.org/git/v3pkg.git/v3
+stdout '^vcs-test.golang.org/git/v3pkg.git/v3 v3.0.0$'
+
+go get -d vcs-test.golang.org/git/empty-v2-without-v1.git/v2@v2.0.0
+
+go list -m vcs-test.golang.org/git/empty-v2-without-v1.git/v2
+stdout '^vcs-test.golang.org/git/empty-v2-without-v1.git/v2 v2.0.0$'
+
+-- go.mod --
+module example.com
+go 1.13
diff --git a/src/cmd/go/testdata/script/mod_get_patterns.txt b/src/cmd/go/testdata/script/mod_get_patterns.txt
index bfab70090c..8adc4b0c06 100644
--- a/src/cmd/go/testdata/script/mod_get_patterns.txt
+++ b/src/cmd/go/testdata/script/mod_get_patterns.txt
@@ -10,11 +10,11 @@ grep 'require rsc.io/quote' go.mod
 
 cp go.mod.orig go.mod
 ! go get -d rsc.io/quote/x...
-stderr 'go get rsc.io/quote/x...: module rsc.io/quote@upgrade \(v1.5.2\) found, but does not contain packages matching rsc.io/quote/x...'
+stderr 'go get rsc.io/quote/x...: module rsc.io/quote@upgrade found \(v1.5.2\), but does not contain packages matching rsc.io/quote/x...'
 ! grep 'require rsc.io/quote' go.mod
 
 ! go get -d rsc.io/quote/x/...
-stderr 'go get rsc.io/quote/x/...: module rsc.io/quote@upgrade \(v1.5.2\) found, but does not contain packages matching rsc.io/quote/x/...'
+stderr 'go get rsc.io/quote/x/...: module rsc.io/quote@upgrade found \(v1.5.2\), but does not contain packages matching rsc.io/quote/x/...'
 ! grep 'require rsc.io/quote' go.mod
 
 # If a pattern matches no packages within a module, the module should not
diff --git a/src/cmd/go/testdata/script/mod_get_trailing_slash.txt b/src/cmd/go/testdata/script/mod_get_trailing_slash.txt
new file mode 100644
index 0000000000..7b5d90c50b
--- /dev/null
+++ b/src/cmd/go/testdata/script/mod_get_trailing_slash.txt
@@ -0,0 +1,30 @@
+# go list should succeed to load a package ending with ".go" if the path does
+# not correspond to an existing local file. Listing a pattern ending with
+# ".go/" should try to list a package regardless of whether a file exists at the
+# path without the suffixed "/" or not.
+go list example.com/dotgo.go
+stdout ^example.com/dotgo.go$
+go list example.com/dotgo.go/
+stdout ^example.com/dotgo.go$
+
+# go get -d should succeed in either case, with or without a version.
+# Arguments are interpreted as packages or package patterns with versions,
+# not source files.
+go get -d example.com/dotgo.go
+go get -d example.com/dotgo.go/
+go get -d example.com/dotgo.go@v1.0.0
+go get -d example.com/dotgo.go/@v1.0.0
+
+# go get (without -d) should also succeed in either case.
+[short] skip
+go get example.com/dotgo.go
+go get example.com/dotgo.go/
+go get example.com/dotgo.go@v1.0.0
+go get example.com/dotgo.go/@v1.0.0
+
+-- go.mod --
+module m
+
+go 1.13
+
+require example.com/dotgo.go v1.0.0
diff --git a/src/cmd/go/testdata/script/mod_list_upgrade.txt b/src/cmd/go/testdata/script/mod_list_upgrade.txt
index f2d0649092..474df0dc26 100644
--- a/src/cmd/go/testdata/script/mod_list_upgrade.txt
+++ b/src/cmd/go/testdata/script/mod_list_upgrade.txt
@@ -1,28 +1,8 @@
 env GO111MODULE=on
 
-# If the current version is not latest, 'go list -u' should include its upgrade.
 go list -m -u all
 stdout 'rsc.io/quote v1.2.0 \[v1\.5\.2\]'
 
-# If the current version is latest, 'go list -u' should omit the upgrade.
-go get -d rsc.io/quote@v1.5.2
-go list -m -u all
-stdout 'rsc.io/quote v1.5.2$'
-
-# If the current version is newer than latest, 'go list -u' should
-# omit the upgrade.
-go get -d rsc.io/quote@v1.5.3-pre1
-go list -m -u all
-stdout 'rsc.io/quote v1.5.3-pre1$'
-
-# If the current build list has a higher version and the user asks about
-# a lower one, -u should report the upgrade for the lower one
-# but leave the build list unchanged.
-go list -m -u rsc.io/quote@v1.5.1
-stdout 'rsc.io/quote v1.5.1 \[v1.5.2\]$'
-go list -m -u rsc.io/quote
-stdout 'rsc.io/quote v1.5.3-pre1$'
-
 -- go.mod --
 module x
 require rsc.io/quote v1.2.0
diff --git a/src/cmd/go/testdata/script/mod_replace.txt b/src/cmd/go/testdata/script/mod_replace.txt
index 35824b3a8a..e4301b50d0 100644
--- a/src/cmd/go/testdata/script/mod_replace.txt
+++ b/src/cmd/go/testdata/script/mod_replace.txt
@@ -38,6 +38,13 @@ grep 'not-rsc.io/quote/v3 v3.1.0' go.mod
 exec ./a5.exe
 stdout 'Concurrency is not parallelism.'
 
+# Error messages for modules not found in replacements should
+# indicate the replacement module.
+cp go.mod.orig go.mod
+go mod edit -replace=rsc.io/quote/v3=./local/rsc.io/quote/v3
+! go get -d rsc.io/quote/v3/missing-package
+stderr 'module rsc.io/quote/v3@upgrade found \(v3.0.0, replaced by ./local/rsc.io/quote/v3\), but does not contain package'
+
 -- go.mod --
 module quoter
 
diff --git a/src/cmd/go/testdata/script/test_timeout.txt b/src/cmd/go/testdata/script/test_timeout.txt
index 8dead0a439..4de4df4508 100644
--- a/src/cmd/go/testdata/script/test_timeout.txt
+++ b/src/cmd/go/testdata/script/test_timeout.txt
@@ -2,12 +2,13 @@
 env GO111MODULE=off
 cd a
 
-# No timeout is passed via 'go test' command.
-go test -v
+# If no timeout is set explicitly, 'go test' should set
+# -test.timeout to its internal deadline.
+go test -v . --
 stdout '10m0s'
 
-# Timeout is passed via 'go test' command.
-go test -v -timeout 30m
+# An explicit -timeout argument should be propagated to -test.timeout.
+go test -v -timeout 30m . --
 stdout '30m0s'
 
 -- a/timeout_test.go --
@@ -19,4 +20,4 @@ import (
 )
 func TestTimeout(t *testing.T) {
 	fmt.Println(flag.Lookup("test.timeout").Value.String())
-}
\ No newline at end of file
+}
diff --git a/src/crypto/ecdsa/ecdsa.go b/src/crypto/ecdsa/ecdsa.go
index be01a29606..22de2a5661 100644
--- a/src/crypto/ecdsa/ecdsa.go
+++ b/src/crypto/ecdsa/ecdsa.go
@@ -225,21 +225,14 @@ func Sign(rand io.Reader, priv *PrivateKey, hash []byte) (r, s *big.Int, err err
 
 	// See [NSA] 3.4.1
 	c := priv.PublicKey.Curve
-	e := hashToInt(hash, c)
-	r, s, err = sign(priv, &csprng, c, e)
-	return
-}
-
-func signGeneric(priv *PrivateKey, csprng *cipher.StreamReader, c elliptic.Curve, e *big.Int) (r, s *big.Int, err error) {
 	N := c.Params().N
 	if N.Sign() == 0 {
 		return nil, nil, errZeroParam
 	}
-
 	var k, kInv *big.Int
 	for {
 		for {
-			k, err = randFieldElement(c, *csprng)
+			k, err = randFieldElement(c, csprng)
 			if err != nil {
 				r = nil
 				return
@@ -257,6 +250,8 @@ func signGeneric(priv *PrivateKey, csprng *cipher.StreamReader, c elliptic.Curve
 				break
 			}
 		}
+
+		e := hashToInt(hash, c)
 		s = new(big.Int).Mul(priv.D, r)
 		s.Add(s, e)
 		s.Mul(s, kInv)
@@ -265,6 +260,7 @@ func signGeneric(priv *PrivateKey, csprng *cipher.StreamReader, c elliptic.Curve
 			break
 		}
 	}
+
 	return
 }
 
@@ -291,12 +287,8 @@ func Verify(pub *PublicKey, hash []byte, r, s *big.Int) bool {
 		return false
 	}
 	e := hashToInt(hash, c)
-	return verify(pub, c, e, r, s)
-}
 
-func verifyGeneric(pub *PublicKey, c elliptic.Curve, e, r, s *big.Int) bool {
 	var w *big.Int
-	N := c.Params().N
 	if in, ok := c.(invertible); ok {
 		w = in.Inverse(s)
 	} else {
diff --git a/src/crypto/ecdsa/ecdsa_noasm.go b/src/crypto/ecdsa/ecdsa_noasm.go
deleted file mode 100644
index 2dfdb866d6..0000000000
--- a/src/crypto/ecdsa/ecdsa_noasm.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.
-
-// +build !s390x
-
-package ecdsa
-
-import (
-	"crypto/cipher"
-	"crypto/elliptic"
-	"math/big"
-)
-
-func sign(priv *PrivateKey, csprng *cipher.StreamReader, c elliptic.Curve, e *big.Int) (r, s *big.Int, err error) {
-	r, s, err = signGeneric(priv, csprng, c, e)
-	return
-}
-
-func verify(pub *PublicKey, c elliptic.Curve, e, r, s *big.Int) bool {
-	return verifyGeneric(pub, c, e, r, s)
-}
diff --git a/src/crypto/ecdsa/ecdsa_s390x.go b/src/crypto/ecdsa/ecdsa_s390x.go
deleted file mode 100644
index f07c3bf50c..0000000000
--- a/src/crypto/ecdsa/ecdsa_s390x.go
+++ /dev/null
@@ -1,153 +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.
-
-// +build s390x,!gccgo
-
-package ecdsa
-
-import (
-	"crypto/cipher"
-	"crypto/elliptic"
-	"internal/cpu"
-	"math/big"
-)
-
-// s390x accelerated signatures
-//go:noescape
-func kdsaSig(fc uint64, block *[1720]byte) (errn uint64)
-
-type signverify int
-
-const (
-	signing signverify = iota
-	verifying
-)
-
-// bufferOffsets represents the offset of a particular parameter in
-// the buffer passed to the KDSA instruction.
-type bufferOffsets struct {
-	baseSize       int
-	hashSize       int
-	offsetHash     int
-	offsetKey1     int
-	offsetRNorKey2 int
-	offsetR        int
-	offsetS        int
-	functionCode   uint64
-}
-
-func canUseKDSA(sv signverify, c elliptic.Curve, bo *bufferOffsets) bool {
-	if !cpu.S390X.HasECDSA {
-		return false
-	}
-
-	switch c.Params().Name {
-	case "P-256":
-		bo.baseSize = 32
-		bo.hashSize = 32
-		bo.offsetHash = 64
-		bo.offsetKey1 = 96
-		bo.offsetRNorKey2 = 128
-		bo.offsetR = 0
-		bo.offsetS = 32
-		if sv == signing {
-			bo.functionCode = 137
-		} else {
-			bo.functionCode = 1
-		}
-		return true
-	case "P-384":
-		bo.baseSize = 48
-		bo.hashSize = 48
-		bo.offsetHash = 96
-		bo.offsetKey1 = 144
-		bo.offsetRNorKey2 = 192
-		bo.offsetR = 0
-		bo.offsetS = 48
-		if sv == signing {
-			bo.functionCode = 138
-		} else {
-			bo.functionCode = 2
-		}
-		return true
-	case "P-521":
-		bo.baseSize = 66
-		bo.hashSize = 80
-		bo.offsetHash = 160
-		bo.offsetKey1 = 254
-		bo.offsetRNorKey2 = 334
-		bo.offsetR = 14
-		bo.offsetS = 94
-		if sv == signing {
-			bo.functionCode = 139
-		} else {
-			bo.functionCode = 3
-		}
-		return true
-	}
-	return false
-}
-
-// zeroExtendAndCopy pads src with leading zeros until it has the size given.
-// It then copies the padded src into the dst. Bytes beyond size in dst are
-// not modified.
-func zeroExtendAndCopy(dst, src []byte, size int) {
-	nz := size - len(src)
-	if nz < 0 {
-		panic("src is too long")
-	}
-	// the compiler should replace this loop with a memclr call
-	z := dst[:nz]
-	for i := range z {
-		z[i] = 0
-	}
-	copy(dst[nz:size], src[:size-nz])
-	return
-}
-
-func sign(priv *PrivateKey, csprng *cipher.StreamReader, c elliptic.Curve, e *big.Int) (r, s *big.Int, err error) {
-	var bo bufferOffsets
-	if canUseKDSA(signing, c, &bo) && e.Sign() != 0 {
-		var buffer [1720]byte
-		for {
-			var k *big.Int
-			k, err = randFieldElement(c, csprng)
-			if err != nil {
-				return nil, nil, err
-			}
-			zeroExtendAndCopy(buffer[bo.offsetHash:], e.Bytes(), bo.hashSize)
-			zeroExtendAndCopy(buffer[bo.offsetKey1:], priv.D.Bytes(), bo.baseSize)
-			zeroExtendAndCopy(buffer[bo.offsetRNorKey2:], k.Bytes(), bo.baseSize)
-			errn := kdsaSig(bo.functionCode, &buffer)
-			if errn == 2 {
-				return nil, nil, errZeroParam
-			}
-			if errn == 0 { // success == 0 means successful signing
-				r = new(big.Int)
-				r.SetBytes(buffer[bo.offsetR : bo.offsetR+bo.baseSize])
-				s = new(big.Int)
-				s.SetBytes(buffer[bo.offsetS : bo.offsetS+bo.baseSize])
-				return
-			}
-			//at this point, it must be that errn == 1: retry
-		}
-	}
-	r, s, err = signGeneric(priv, csprng, c, e)
-	return
-}
-
-func verify(pub *PublicKey, c elliptic.Curve, e, r, s *big.Int) bool {
-	var bo bufferOffsets
-	if canUseKDSA(verifying, c, &bo) && e.Sign() != 0 {
-		var buffer [1720]byte
-		zeroExtendAndCopy(buffer[bo.offsetR:], r.Bytes(), bo.baseSize)
-		zeroExtendAndCopy(buffer[bo.offsetS:], s.Bytes(), bo.baseSize)
-		zeroExtendAndCopy(buffer[bo.offsetHash:], e.Bytes(), bo.hashSize)
-		zeroExtendAndCopy(buffer[bo.offsetKey1:], pub.X.Bytes(), bo.baseSize)
-		zeroExtendAndCopy(buffer[bo.offsetRNorKey2:], pub.Y.Bytes(), bo.baseSize)
-		errn := kdsaSig(bo.functionCode, &buffer)
-		return errn == 0
-	}
-	return verifyGeneric(pub, c, e, r, s)
-}
diff --git a/src/crypto/ecdsa/ecdsa_s390x.s b/src/crypto/ecdsa/ecdsa_s390x.s
deleted file mode 100644
index 6ee00ce79c..0000000000
--- a/src/crypto/ecdsa/ecdsa_s390x.s
+++ /dev/null
@@ -1,31 +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.
-
-#include "textflag.h"
-
-// func kdsaSig(fc uint64, block *[1720]byte) (errn uint64)
-TEXT ·kdsaSig(SB), NOSPLIT|NOFRAME, $0-24
-	MOVD fc+0(FP), R0    // function code
-	MOVD block+8(FP), R1 // address parameter block
-
-loop:
-	WORD $0xB93A0008 // compute digital signature authentication
-	BVS  loop        // branch back if interrupted
-	BEQ  success     // signature creation successful
-	BGT  retry       // signing unsuccessful, but retry with new CSPRN
-
-error:
-	MOVD $2, R2          // fallthrough indicates fatal error
-	MOVD R2, errn+16(FP) // return 2 - sign/verify abort
-	RET
-
-retry:
-	MOVD $1, R2
-	MOVD R2, errn+16(FP) // return 1 - sign/verify was unsuccessful -- if sign, retry with new RN
-	RET
-
-success:
-	MOVD $0, R2
-	MOVD R2, errn+16(FP) // return 0 - sign/verify was successful
-	RET
diff --git a/src/crypto/ecdsa/ecdsa_s390x_test.go b/src/crypto/ecdsa/ecdsa_s390x_test.go
deleted file mode 100644
index 80babc9cb4..0000000000
--- a/src/crypto/ecdsa/ecdsa_s390x_test.go
+++ /dev/null
@@ -1,33 +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.
-
-// +build s390x,!gccgo
-
-package ecdsa
-
-import (
-	"crypto/elliptic"
-	"testing"
-)
-
-func TestNoAsm(t *testing.T) {
-	curves := [...]elliptic.Curve{
-		elliptic.P256(),
-		elliptic.P384(),
-		elliptic.P521(),
-	}
-
-	for _, curve := range curves {
-		// override the name of the curve to stop the assembly path being taken
-		params := *curve.Params()
-		name := params.Name
-		params.Name = name + "_GENERIC_OVERRIDE"
-
-		testKeyGeneration(t, &params, name)
-		testSignAndVerify(t, &params, name)
-		testNonceSafety(t, &params, name)
-		testINDCCA(t, &params, name)
-		testNegativeInputs(t, &params, name)
-	}
-}
diff --git a/src/errors/errors.go b/src/errors/errors.go
index 85d4260762..d923ad4b70 100644
--- a/src/errors/errors.go
+++ b/src/errors/errors.go
@@ -13,16 +13,16 @@
 //
 // If e.Unwrap() returns a non-nil error w, then we say that e wraps w.
 //
+// Unwrap unpacks wrapped errors. If its argument's type has an
+// Unwrap method, it calls the method once. Otherwise, it returns nil.
+//
 // A simple way to create wrapped errors is to call fmt.Errorf and apply the %w verb
 // to the error argument:
 //
-//	fmt.Errorf("... %w ...", ..., err, ...).Unwrap()
+//	errors.Unwrap(fmt.Errorf("... %w ...", ..., err, ...))
 //
 // returns err.
 //
-// Unwrap unpacks wrapped errors. If its argument's type has an
-// Unwrap method, it calls the method once. Otherwise, it returns nil.
-//
 // Is unwraps its first argument sequentially looking for an error that matches the
 // second. It reports whether it finds a match. It should be used in preference to
 // simple equality checks:
diff --git a/src/internal/syscall/windows/mksyscall.go b/src/internal/syscall/windows/mksyscall.go
index 0bf87dc95c..95e36f7aa3 100644
--- a/src/internal/syscall/windows/mksyscall.go
+++ b/src/internal/syscall/windows/mksyscall.go
@@ -6,4 +6,4 @@
 
 package windows
 
-//go:generate go run $GOROOT/src/syscall/mksyscall_windows.go -output zsyscall_windows.go syscall_windows.go security_windows.go psapi_windows.go symlink_windows.go
+//go:generate go run golang.org/x/sys/windows/mkwinsyscall -output zsyscall_windows.go syscall_windows.go security_windows.go psapi_windows.go symlink_windows.go
diff --git a/src/internal/syscall/windows/registry/mksyscall.go b/src/internal/syscall/windows/registry/mksyscall.go
index fa8e27e8ff..cb4906a7b2 100644
--- a/src/internal/syscall/windows/registry/mksyscall.go
+++ b/src/internal/syscall/windows/registry/mksyscall.go
@@ -6,4 +6,4 @@
 
 package registry
 
-//go:generate go run $GOROOT/src/syscall/mksyscall_windows.go -output zsyscall_windows.go syscall.go
+//go:generate go run golang.org/x/sys/windows/mkwinsyscall -output zsyscall_windows.go syscall.go
diff --git a/src/log/syslog/syslog_test.go b/src/log/syslog/syslog_test.go
index 447654a874..8a28d67c98 100644
--- a/src/log/syslog/syslog_test.go
+++ b/src/log/syslog/syslog_test.go
@@ -134,6 +134,9 @@ func startServer(n, la string, done chan<- string) (addr string, sock io.Closer,
 }
 
 func TestWithSimulated(t *testing.T) {
+	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
+		t.Skipf("sysctl is not supported on iOS")
+	}
 	t.Parallel()
 	msg := "Test 123"
 	var transport []string
@@ -272,6 +275,9 @@ func check(t *testing.T, in, out string) {
 }
 
 func TestWrite(t *testing.T) {
+	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
+		t.Skipf("sysctl is not supported on iOS")
+	}
 	t.Parallel()
 	tests := []struct {
 		pri Priority
diff --git a/src/net/dnsclient_unix.go b/src/net/dnsclient_unix.go
index e0a7ef8552..c90892b833 100644
--- a/src/net/dnsclient_unix.go
+++ b/src/net/dnsclient_unix.go
@@ -765,6 +765,14 @@ func (r *Resolver) goLookupPTR(ctx context.Context, addr string) ([]string, erro
 			}
 		}
 		if h.Type != dnsmessage.TypePTR {
+			err := p.SkipAnswer()
+			if err != nil {
+				return nil, &DNSError{
+					Err:    "cannot marshal DNS message",
+					Name:   addr,
+					Server: server,
+				}
+			}
 			continue
 		}
 		ptr, err := p.PTRResource()
diff --git a/src/net/dnsclient_unix_test.go b/src/net/dnsclient_unix_test.go
index 98304d36ea..31cb6f721a 100644
--- a/src/net/dnsclient_unix_test.go
+++ b/src/net/dnsclient_unix_test.go
@@ -1753,3 +1753,50 @@ func TestDNSUseTCP(t *testing.T) {
 		t.Fatal("exchange failed:", err)
 	}
 }
+
+// Issue 34660: PTR response with non-PTR answers should ignore non-PTR
+func TestPTRandNonPTR(t *testing.T) {
+	fake := fakeDNSServer{
+		rh: func(n, _ string, q dnsmessage.Message, _ time.Time) (dnsmessage.Message, error) {
+			r := dnsmessage.Message{
+				Header: dnsmessage.Header{
+					ID:       q.Header.ID,
+					Response: true,
+					RCode:    dnsmessage.RCodeSuccess,
+				},
+				Questions: q.Questions,
+				Answers: []dnsmessage.Resource{
+					{
+						Header: dnsmessage.ResourceHeader{
+							Name:  q.Questions[0].Name,
+							Type:  dnsmessage.TypePTR,
+							Class: dnsmessage.ClassINET,
+						},
+						Body: &dnsmessage.PTRResource{
+							PTR: dnsmessage.MustNewName("golang.org."),
+						},
+					},
+					{
+						Header: dnsmessage.ResourceHeader{
+							Name:  q.Questions[0].Name,
+							Type:  dnsmessage.TypeTXT,
+							Class: dnsmessage.ClassINET,
+						},
+						Body: &dnsmessage.TXTResource{
+							TXT: []string{"PTR 8 6 60 ..."}, // fake RRSIG
+						},
+					},
+				},
+			}
+			return r, nil
+		},
+	}
+	r := Resolver{PreferGo: true, Dial: fake.DialContext}
+	names, err := r.lookupAddr(context.Background(), "192.0.2.123")
+	if err != nil {
+		t.Fatalf("LookupAddr: %v", err)
+	}
+	if want := []string{"golang.org."}; !reflect.DeepEqual(names, want) {
+		t.Errorf("names = %q; want %q", names, want)
+	}
+}
diff --git a/src/net/http/client.go b/src/net/http/client.go
index 65a9d51cc6..20496d2f0e 100644
--- a/src/net/http/client.go
+++ b/src/net/http/client.go
@@ -238,7 +238,7 @@ func send(ireq *Request, rt RoundTripper, deadline time.Time) (resp *Response, d
 		username := u.Username()
 		password, _ := u.Password()
 		forkReq()
-		req.Header = ireq.Header.Clone()
+		req.Header = cloneOrMakeHeader(ireq.Header)
 		req.Header.Set("Authorization", "Basic "+basicAuth(username, password))
 	}
 
@@ -668,7 +668,7 @@ func (c *Client) makeHeadersCopier(ireq *Request) func(*Request) {
 	// The headers to copy are from the very initial request.
 	// We use a closured callback to keep a reference to these original headers.
 	var (
-		ireqhdr  = ireq.Header.Clone()
+		ireqhdr  = cloneOrMakeHeader(ireq.Header)
 		icookies map[string][]*Cookie
 	)
 	if c.Jar != nil && ireq.Header.Get("Cookie") != "" {
diff --git a/src/net/http/clone.go b/src/net/http/clone.go
index 5f2784d280..3a3375bff7 100644
--- a/src/net/http/clone.go
+++ b/src/net/http/clone.go
@@ -62,3 +62,13 @@ func cloneMultipartFileHeader(fh *multipart.FileHeader) *multipart.FileHeader {
 	fh2.Header = textproto.MIMEHeader(Header(fh.Header).Clone())
 	return fh2
 }
+
+// cloneOrMakeHeader invokes Header.Clone but if the
+// result is nil, it'll instead make and return a non-nil Header.
+func cloneOrMakeHeader(hdr Header) Header {
+	clone := hdr.Clone()
+	if clone == nil {
+		clone = make(Header)
+	}
+	return clone
+}
diff --git a/src/net/http/export_test.go b/src/net/http/export_test.go
index d265cd3f72..e5c06a8903 100644
--- a/src/net/http/export_test.go
+++ b/src/net/http/export_test.go
@@ -208,6 +208,30 @@ func (t *Transport) PutIdleTestConn(scheme, addr string) bool {
 	}) == nil
 }
 
+// PutIdleTestConnH2 reports whether it was able to insert a fresh
+// HTTP/2 persistConn for scheme, addr into the idle connection pool.
+func (t *Transport) PutIdleTestConnH2(scheme, addr string, alt RoundTripper) bool {
+	key := connectMethodKey{"", scheme, addr, false}
+
+	if t.MaxConnsPerHost > 0 {
+		// Transport is tracking conns-per-host.
+		// Increment connection count to account
+		// for new persistConn created below.
+		t.connsPerHostMu.Lock()
+		if t.connsPerHost == nil {
+			t.connsPerHost = make(map[connectMethodKey]int)
+		}
+		t.connsPerHost[key]++
+		t.connsPerHostMu.Unlock()
+	}
+
+	return t.tryPutIdleConn(&persistConn{
+		t:        t,
+		alt:      alt,
+		cacheKey: key,
+	}) == nil
+}
+
 // All test hooks must be non-nil so they can be called directly,
 // but the tests use nil to mean hook disabled.
 func unnilTestHook(f *func()) {
diff --git a/src/net/http/h2_bundle.go b/src/net/http/h2_bundle.go
index 53cc5bd1b8..e9a55f388a 100644
--- a/src/net/http/h2_bundle.go
+++ b/src/net/http/h2_bundle.go
@@ -10148,7 +10148,8 @@ type http2randomWriteScheduler struct {
 	zero http2writeQueue
 
 	// sq contains the stream-specific queues, keyed by stream ID.
-	// When a stream is idle or closed, it's deleted from the map.
+	// When a stream is idle, closed, or emptied, it's deleted
+	// from the map.
 	sq map[uint32]*http2writeQueue
 
 	// pool of empty queues for reuse.
@@ -10192,8 +10193,12 @@ func (ws *http2randomWriteScheduler) Pop() (http2FrameWriteRequest, bool) {
 		return ws.zero.shift(), true
 	}
 	// Iterate over all non-idle streams until finding one that can be consumed.
-	for _, q := range ws.sq {
+	for streamID, q := range ws.sq {
 		if wr, ok := q.consume(math.MaxInt32); ok {
+			if q.empty() {
+				delete(ws.sq, streamID)
+				ws.queuePool.put(q)
+			}
 			return wr, true
 		}
 	}
diff --git a/src/net/http/header_test.go b/src/net/http/header_test.go
index 51fcab103b..4789362919 100644
--- a/src/net/http/header_test.go
+++ b/src/net/http/header_test.go
@@ -7,6 +7,7 @@ package http
 import (
 	"bytes"
 	"internal/race"
+	"reflect"
 	"runtime"
 	"testing"
 	"time"
@@ -219,3 +220,34 @@ func TestHeaderWriteSubsetAllocs(t *testing.T) {
 		t.Errorf("allocs = %g; want 0", n)
 	}
 }
+
+// Issue 34878: test that every call to
+// cloneOrMakeHeader never returns a nil Header.
+func TestCloneOrMakeHeader(t *testing.T) {
+	tests := []struct {
+		name     string
+		in, want Header
+	}{
+		{"nil", nil, Header{}},
+		{"empty", Header{}, Header{}},
+		{
+			name: "non-empty",
+			in:   Header{"foo": {"bar"}},
+			want: Header{"foo": {"bar"}},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := cloneOrMakeHeader(tt.in)
+			if got == nil {
+				t.Fatal("unexpected nil Header")
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Fatalf("Got:  %#v\nWant: %#v", got, tt.want)
+			}
+			got.Add("A", "B")
+			got.Get("A")
+		})
+	}
+}
diff --git a/src/net/http/request_test.go b/src/net/http/request_test.go
index b072f95802..bb06d922f0 100644
--- a/src/net/http/request_test.go
+++ b/src/net/http/request_test.go
@@ -826,6 +826,34 @@ func TestWithContextDeepCopiesURL(t *testing.T) {
 	}
 }
 
+func TestNoPanicOnRoundTripWithBasicAuth_h1(t *testing.T) {
+	testNoPanicWithBasicAuth(t, h1Mode)
+}
+
+func TestNoPanicOnRoundTripWithBasicAuth_h2(t *testing.T) {
+	testNoPanicWithBasicAuth(t, h2Mode)
+}
+
+// Issue 34878: verify we don't panic when including basic auth (Go 1.13 regression)
+func testNoPanicWithBasicAuth(t *testing.T, h2 bool) {
+	defer afterTest(t)
+	cst := newClientServerTest(t, h2, HandlerFunc(func(w ResponseWriter, r *Request) {}))
+	defer cst.close()
+
+	u, err := url.Parse(cst.ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	u.User = url.UserPassword("foo", "bar")
+	req := &Request{
+		URL:    u,
+		Method: "GET",
+	}
+	if _, err := cst.c.Do(req); err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+}
+
 // verify that NewRequest sets Request.GetBody and that it works
 func TestNewRequestGetBody(t *testing.T) {
 	tests := []struct {
diff --git a/src/net/http/server.go b/src/net/http/server.go
index f554c81300..95a5eabaa2 100644
--- a/src/net/http/server.go
+++ b/src/net/http/server.go
@@ -3267,7 +3267,6 @@ type timeoutWriter struct {
 }
 
 var _ Pusher = (*timeoutWriter)(nil)
-var _ Flusher = (*timeoutWriter)(nil)
 
 // Push implements the Pusher interface.
 func (tw *timeoutWriter) Push(target string, opts *PushOptions) error {
@@ -3277,14 +3276,6 @@ func (tw *timeoutWriter) Push(target string, opts *PushOptions) error {
 	return ErrNotSupported
 }
 
-// Flush implements the Flusher interface.
-func (tw *timeoutWriter) Flush() {
-	f, ok := tw.w.(Flusher)
-	if ok {
-		f.Flush()
-	}
-}
-
 func (tw *timeoutWriter) Header() Header { return tw.h }
 
 func (tw *timeoutWriter) Write(p []byte) (int, error) {
diff --git a/src/net/http/transport.go b/src/net/http/transport.go
index ee279877e0..caa4bdc36f 100644
--- a/src/net/http/transport.go
+++ b/src/net/http/transport.go
@@ -539,6 +539,7 @@ func (t *Transport) roundTrip(req *Request) (*Response, error) {
 		}
 		if http2isNoCachedConnError(err) {
 			t.removeIdleConn(pconn)
+			t.decConnsPerHost(pconn.cacheKey)
 		} else if !pconn.shouldRetryRequest(req, err) {
 			// Issue 16465: return underlying net.Conn.Read error from peek,
 			// as we've historically done.
@@ -1206,7 +1207,9 @@ func (t *Transport) getConn(treq *transportRequest, cm connectMethod) (pc *persi
 	// Queue for idle connection.
 	if delivered := t.queueForIdleConn(w); delivered {
 		pc := w.pc
-		if trace != nil && trace.GotConn != nil {
+		// Trace only for HTTP/1.
+		// HTTP/2 calls trace.GotConn itself.
+		if pc.alt == nil && trace != nil && trace.GotConn != nil {
 			trace.GotConn(pc.gotIdleConnTrace(pc.idleAt))
 		}
 		// set request canceler to some non-nil function so we
diff --git a/src/net/http/transport_test.go b/src/net/http/transport_test.go
index 181d944d85..e43c8956ee 100644
--- a/src/net/http/transport_test.go
+++ b/src/net/http/transport_test.go
@@ -3562,6 +3562,76 @@ func TestTransportCloseIdleConnsThenReturn(t *testing.T) {
 	wantIdle("after final put", 1)
 }
 
+// Test for issue 34282
+// Ensure that getConn doesn't call the GotConn trace hook on a HTTP/2 idle conn
+func TestTransportTraceGotConnH2IdleConns(t *testing.T) {
+	tr := &Transport{}
+	wantIdle := func(when string, n int) bool {
+		got := tr.IdleConnCountForTesting("https", "example.com:443") // key used by PutIdleTestConnH2
+		if got == n {
+			return true
+		}
+		t.Errorf("%s: idle conns = %d; want %d", when, got, n)
+		return false
+	}
+	wantIdle("start", 0)
+	alt := funcRoundTripper(func() {})
+	if !tr.PutIdleTestConnH2("https", "example.com:443", alt) {
+		t.Fatal("put failed")
+	}
+	wantIdle("after put", 1)
+	ctx := httptrace.WithClientTrace(context.Background(), &httptrace.ClientTrace{
+		GotConn: func(httptrace.GotConnInfo) {
+			// tr.getConn should leave it for the HTTP/2 alt to call GotConn.
+			t.Error("GotConn called")
+		},
+	})
+	req, _ := NewRequestWithContext(ctx, MethodGet, "https://example.com", nil)
+	_, err := tr.RoundTrip(req)
+	if err != errFakeRoundTrip {
+		t.Errorf("got error: %v; want %q", err, errFakeRoundTrip)
+	}
+	wantIdle("after round trip", 1)
+}
+
+func TestTransportRemovesH2ConnsAfterIdle(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+
+	trFunc := func(tr *Transport) {
+		tr.MaxConnsPerHost = 1
+		tr.MaxIdleConnsPerHost = 1
+		tr.IdleConnTimeout = 10 * time.Millisecond
+	}
+	cst := newClientServerTest(t, h2Mode, HandlerFunc(func(w ResponseWriter, r *Request) {}), trFunc)
+	defer cst.close()
+
+	if _, err := cst.c.Get(cst.ts.URL); err != nil {
+		t.Fatalf("got error: %s", err)
+	}
+
+	time.Sleep(100 * time.Millisecond)
+	got := make(chan error)
+	go func() {
+		if _, err := cst.c.Get(cst.ts.URL); err != nil {
+			got <- err
+		}
+		close(got)
+	}()
+
+	timeout := time.NewTimer(5 * time.Second)
+	defer timeout.Stop()
+	select {
+	case err := <-got:
+		if err != nil {
+			t.Fatalf("got error: %s", err)
+		}
+	case <-timeout.C:
+		t.Fatal("request never completed")
+	}
+}
+
 // This tests that an client requesting a content range won't also
 // implicitly ask for gzip support. If they want that, they need to do it
 // on their own.
diff --git a/src/net/interface_test.go b/src/net/interface_test.go
index fb6032fbc0..6cdfb6265f 100644
--- a/src/net/interface_test.go
+++ b/src/net/interface_test.go
@@ -51,6 +51,9 @@ func ipv6LinkLocalUnicastAddr(ifi *Interface) string {
 }
 
 func TestInterfaces(t *testing.T) {
+	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
+		t.Skipf("sysctl is not supported on iOS")
+	}
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)
@@ -82,6 +85,9 @@ func TestInterfaces(t *testing.T) {
 }
 
 func TestInterfaceAddrs(t *testing.T) {
+	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
+		t.Skipf("sysctl is not supported on iOS")
+	}
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)
@@ -101,6 +107,9 @@ func TestInterfaceAddrs(t *testing.T) {
 }
 
 func TestInterfaceUnicastAddrs(t *testing.T) {
+	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
+		t.Skipf("sysctl is not supported on iOS")
+	}
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)
@@ -128,6 +137,9 @@ func TestInterfaceUnicastAddrs(t *testing.T) {
 }
 
 func TestInterfaceMulticastAddrs(t *testing.T) {
+	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
+		t.Skipf("sysctl is not supported on iOS")
+	}
 	ift, err := Interfaces()
 	if err != nil {
 		t.Fatal(err)
diff --git a/src/os/os_test.go b/src/os/os_test.go
index 6c88d7e8b8..b94ab0d232 100644
--- a/src/os/os_test.go
+++ b/src/os/os_test.go
@@ -1521,6 +1521,9 @@ func testWindowsHostname(t *testing.T, hostname string) {
 }
 
 func TestHostname(t *testing.T) {
+	if runtime.GOOS == "darwin" && (runtime.GOARCH == "arm" || runtime.GOARCH == "arm64") {
+		t.Skipf("sysctl is not supported on iOS")
+	}
 	hostname, err := Hostname()
 	if err != nil {
 		t.Fatal(err)
@@ -2251,8 +2254,6 @@ func TestPipeThreads(t *testing.T) {
 		t.Skip("skipping on Plan 9; does not support runtime poller")
 	case "js":
 		t.Skip("skipping on js; no support for os.Pipe")
-	case "darwin":
-		t.Skip("skipping on Darwin; issue 33953")
 	}
 
 	threads := 100
diff --git a/src/runtime/export_test.go b/src/runtime/export_test.go
index 6009932056..e4a7faf965 100644
--- a/src/runtime/export_test.go
+++ b/src/runtime/export_test.go
@@ -345,6 +345,9 @@ func ReadMemStatsSlow() (base, slow MemStats) {
 			slow.HeapReleased += uint64(i.span().released())
 		}
 
+		// Unused space in the current arena also counts as released space.
+		slow.HeapReleased += uint64(mheap_.curArena.end - mheap_.curArena.base)
+
 		getg().m.mallocing--
 	})
 
diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go
index 823b556e53..8a6b860c96 100644
--- a/src/runtime/mgc.go
+++ b/src/runtime/mgc.go
@@ -229,6 +229,8 @@ func setGCPercent(in int32) (out int32) {
 		gcSetTriggerRatio(memstats.triggerRatio)
 		unlock(&mheap_.lock)
 	})
+	// Pacing changed, so the scavenger should be awoken.
+	wakeScavenger()
 
 	// If we just disabled GC, wait for any concurrent GC mark to
 	// finish so we always return with no GC running.
@@ -1649,9 +1651,16 @@ func gcMarkTermination(nextTriggerRatio float64) {
 		throw("gc done but gcphase != _GCoff")
 	}
 
+	// Record next_gc and heap_inuse for scavenger.
+	memstats.last_next_gc = memstats.next_gc
+	memstats.last_heap_inuse = memstats.heap_inuse
+
 	// Update GC trigger and pacing for the next cycle.
 	gcSetTriggerRatio(nextTriggerRatio)
 
+	// Pacing changed, so the scavenger should be awoken.
+	wakeScavenger()
+
 	// Update timing memstats
 	now := nanotime()
 	sec, nsec, _ := time_now()
diff --git a/src/runtime/mgcscavenge.go b/src/runtime/mgcscavenge.go
index 45a9eb2b2a..c4394a3d60 100644
--- a/src/runtime/mgcscavenge.go
+++ b/src/runtime/mgcscavenge.go
@@ -17,7 +17,29 @@
 // scavenger's primary goal is to bring the estimated heap RSS of the
 // application down to a goal.
 //
-// That goal is defined as (retainExtraPercent+100) / 100 * next_gc.
+// That goal is defined as:
+//   (retainExtraPercent+100) / 100 * (next_gc / last_next_gc) * last_heap_inuse
+//
+// Essentially, we wish to have the application's RSS track the heap goal, but
+// the heap goal is defined in terms of bytes of objects, rather than pages like
+// RSS. As a result, we need to take into account for fragmentation internal to
+// spans. next_gc / last_next_gc defines the ratio between the current heap goal
+// and the last heap goal, which tells us by how much the heap is growing and
+// shrinking. We estimate what the heap will grow to in terms of pages by taking
+// this ratio and multiplying it by heap_inuse at the end of the last GC, which
+// allows us to account for this additional fragmentation. Note that this
+// procedure makes the assumption that the degree of fragmentation won't change
+// dramatically over the next GC cycle. Overestimating the amount of
+// fragmentation simply results in higher memory use, which will be accounted
+// for by the next pacing up date. Underestimating the fragmentation however
+// could lead to performance degradation. Handling this case is not within the
+// scope of the scavenger. Situations where the amount of fragmentation balloons
+// over the course of a single GC cycle should be considered pathologies,
+// flagged as bugs, and fixed appropriately.
+//
+// An additional factor of retainExtraPercent is added as a buffer to help ensure
+// that there's more unscavenged memory to allocate out of, since each allocation
+// out of scavenged memory incurs a potentially expensive page fault.
 //
 // The goal is updated after each GC and the scavenger's pacing parameters
 // (which live in mheap_) are updated to match. The pacing parameters work much
@@ -81,14 +103,24 @@ func heapRetained() uint64 {
 //
 // mheap_.lock must be held or the world must be stopped.
 func gcPaceScavenger() {
-	// Compute our scavenging goal and align it to a physical page boundary
-	// to make the following calculations more exact.
-	retainedGoal := memstats.next_gc
+	// If we're called before the first GC completed, disable scavenging.
+	// We never scavenge before the 2nd GC cycle anyway (we don't have enough
+	// information about the heap yet) so this is fine, and avoids a fault
+	// or garbage data later.
+	if memstats.last_next_gc == 0 {
+		mheap_.scavengeBytesPerNS = 0
+		return
+	}
+	// Compute our scavenging goal.
+	goalRatio := float64(memstats.next_gc) / float64(memstats.last_next_gc)
+	retainedGoal := uint64(float64(memstats.last_heap_inuse) * goalRatio)
 	// Add retainExtraPercent overhead to retainedGoal. This calculation
 	// looks strange but the purpose is to arrive at an integer division
 	// (e.g. if retainExtraPercent = 12.5, then we get a divisor of 8)
 	// that also avoids the overflow from a multiplication.
 	retainedGoal += retainedGoal / (1.0 / (retainExtraPercent / 100.0))
+	// Align it to a physical page boundary to make the following calculations
+	// a bit more exact.
 	retainedGoal = (retainedGoal + uint64(physPageSize) - 1) &^ (uint64(physPageSize) - 1)
 
 	// Represents where we are now in the heap's contribution to RSS in bytes.
@@ -154,36 +186,41 @@ func gcPaceScavenger() {
 
 	now := nanotime()
 
-	lock(&scavenge.lock)
-
 	// Update all the pacing parameters in mheap with scavenge.lock held,
 	// so that scavenge.gen is kept in sync with the updated values.
 	mheap_.scavengeRetainedGoal = retainedGoal
 	mheap_.scavengeRetainedBasis = retainedNow
 	mheap_.scavengeTimeBasis = now
 	mheap_.scavengeBytesPerNS = float64(totalWork) / float64(totalTime)
-	scavenge.gen++ // increase scavenge generation
-
-	// Wake up background scavenger if needed, since the pacing was just updated.
-	wakeScavengerLocked()
-
-	unlock(&scavenge.lock)
+	mheap_.scavengeGen++ // increase scavenge generation
 }
 
-// State of the background scavenger.
+// Sleep/wait state of the background scavenger.
 var scavenge struct {
 	lock   mutex
 	g      *g
 	parked bool
 	timer  *timer
-	gen    uint32 // read with either lock or mheap_.lock, write with both
+
+	// Generation counter.
+	//
+	// It represents the last generation count (as defined by
+	// mheap_.scavengeGen) checked by the scavenger and is updated
+	// each time the scavenger checks whether it is on-pace.
+	//
+	// Skew between this field and mheap_.scavengeGen is used to
+	// determine whether a new update is available.
+	//
+	// Protected by mheap_.lock.
+	gen uint64
 }
 
-// wakeScavengerLocked unparks the scavenger if necessary. It must be called
+// wakeScavenger unparks the scavenger if necessary. It must be called
 // after any pacing update.
 //
-// scavenge.lock must be held.
-func wakeScavengerLocked() {
+// mheap_.lock and scavenge.lock must not be held.
+func wakeScavenger() {
+	lock(&scavenge.lock)
 	if scavenge.parked {
 		// Try to stop the timer but we don't really care if we succeed.
 		// It's possible that either a timer was never started, or that
@@ -198,11 +235,10 @@ func wakeScavengerLocked() {
 		scavenge.parked = false
 		ready(scavenge.g, 0, true)
 	}
+	unlock(&scavenge.lock)
 }
 
 // scavengeSleep attempts to put the scavenger to sleep for ns.
-// It also checks to see if gen != scavenge.gen before going to sleep,
-// and aborts if true (meaning an update had occurred).
 //
 // Note that this function should only be called by the scavenger.
 //
@@ -210,24 +246,32 @@ func wakeScavengerLocked() {
 // to sleep at all if there's a pending pacing change.
 //
 // Returns false if awoken early (i.e. true means a complete sleep).
-func scavengeSleep(gen uint32, ns int64) bool {
+func scavengeSleep(ns int64) bool {
 	lock(&scavenge.lock)
 
-	// If there was an update, just abort the sleep.
-	if scavenge.gen != gen {
+	// First check if there's a pending update.
+	// If there is one, don't bother sleeping.
+	var hasUpdate bool
+	systemstack(func() {
+		lock(&mheap_.lock)
+		hasUpdate = mheap_.scavengeGen != scavenge.gen
+		unlock(&mheap_.lock)
+	})
+	if hasUpdate {
 		unlock(&scavenge.lock)
 		return false
 	}
 
 	// Set the timer.
+	//
+	// This must happen here instead of inside gopark
+	// because we can't close over any variables without
+	// failing escape analysis.
 	now := nanotime()
 	scavenge.timer.when = now + ns
 	startTimer(scavenge.timer)
 
-	// Park the goroutine. It's fine that we don't publish the
-	// fact that the timer was set; even if the timer wakes up
-	// and fire scavengeReady before we park, it'll block on
-	// scavenge.lock.
+	// Mark ourself as asleep and go to sleep.
 	scavenge.parked = true
 	goparkunlock(&scavenge.lock, waitReasonSleep, traceEvGoSleep, 2)
 
@@ -248,9 +292,7 @@ func bgscavenge(c chan int) {
 
 	scavenge.timer = new(timer)
 	scavenge.timer.f = func(_ interface{}, _ uintptr) {
-		lock(&scavenge.lock)
-		wakeScavengerLocked()
-		unlock(&scavenge.lock)
+		wakeScavenger()
 	}
 
 	c <- 1
@@ -279,14 +321,14 @@ func bgscavenge(c chan int) {
 		released := uintptr(0)
 		park := false
 		ttnext := int64(0)
-		gen := uint32(0)
 
 		// Run on the system stack since we grab the heap lock,
 		// and a stack growth with the heap lock means a deadlock.
 		systemstack(func() {
 			lock(&mheap_.lock)
 
-			gen = scavenge.gen
+			// Update the last generation count that the scavenger has handled.
+			scavenge.gen = mheap_.scavengeGen
 
 			// If background scavenging is disabled or if there's no work to do just park.
 			retained := heapRetained()
@@ -343,7 +385,7 @@ func bgscavenge(c chan int) {
 		if released == 0 {
 			// If we were unable to release anything this may be because there's
 			// no free memory available to scavenge. Go to sleep and try again.
-			if scavengeSleep(gen, retryDelayNS) {
+			if scavengeSleep(retryDelayNS) {
 				// If we successfully slept through the delay, back off exponentially.
 				retryDelayNS *= 2
 			}
@@ -355,7 +397,7 @@ func bgscavenge(c chan int) {
 			// If there's an appreciable amount of time until the next scavenging
 			// goal, just sleep. We'll get woken up if anything changes and this
 			// way we avoid spinning.
-			scavengeSleep(gen, ttnext)
+			scavengeSleep(ttnext)
 			continue
 		}
 
diff --git a/src/runtime/mheap.go b/src/runtime/mheap.go
index 706603aba4..3807050cbe 100644
--- a/src/runtime/mheap.go
+++ b/src/runtime/mheap.go
@@ -107,6 +107,7 @@ type mheap struct {
 	scavengeRetainedBasis uint64
 	scavengeBytesPerNS    float64
 	scavengeRetainedGoal  uint64
+	scavengeGen           uint64 // incremented on each pacing update
 
 	// Page reclaimer state
 
@@ -185,6 +186,12 @@ type mheap struct {
 	// simply blocking GC (by disabling preemption).
 	sweepArenas []arenaIdx
 
+	// curArena is the arena that the heap is currently growing
+	// into. This should always be physPageSize-aligned.
+	curArena struct {
+		base, end uintptr
+	}
+
 	_ uint32 // ensure 64-bit alignment of central
 
 	// central free lists for small size classes.
@@ -1220,16 +1227,6 @@ HaveSpan:
 		// heap_released since we already did so earlier.
 		sysUsed(unsafe.Pointer(s.base()), s.npages<<_PageShift)
 		s.scavenged = false
-
-		// Since we allocated out of a scavenged span, we just
-		// grew the RSS. Mitigate this by scavenging enough free
-		// space to make up for it but only if we need to.
-		//
-		// scavengeLocked may cause coalescing, so prevent
-		// coalescing with s by temporarily changing its state.
-		s.state = mSpanManual
-		h.scavengeIfNeededLocked(s.npages * pageSize)
-		s.state = mSpanFree
 	}
 
 	h.setSpans(s.base(), npage, s)
@@ -1249,29 +1246,78 @@ HaveSpan:
 // h must be locked.
 func (h *mheap) grow(npage uintptr) bool {
 	ask := npage << _PageShift
-	v, size := h.sysAlloc(ask)
-	if v == nil {
-		print("runtime: out of memory: cannot allocate ", ask, "-byte block (", memstats.heap_sys, " in use)\n")
-		return false
-	}
 
-	// Create a fake "in use" span and free it, so that the
-	// right accounting and coalescing happens.
+	nBase := round(h.curArena.base+ask, physPageSize)
+	if nBase > h.curArena.end {
+		// Not enough room in the current arena. Allocate more
+		// arena space. This may not be contiguous with the
+		// current arena, so we have to request the full ask.
+		av, asize := h.sysAlloc(ask)
+		if av == nil {
+			print("runtime: out of memory: cannot allocate ", ask, "-byte block (", memstats.heap_sys, " in use)\n")
+			return false
+		}
+
+		if uintptr(av) == h.curArena.end {
+			// The new space is contiguous with the old
+			// space, so just extend the current space.
+			h.curArena.end = uintptr(av) + asize
+		} else {
+			// The new space is discontiguous. Track what
+			// remains of the current space and switch to
+			// the new space. This should be rare.
+			if size := h.curArena.end - h.curArena.base; size != 0 {
+				h.growAddSpan(unsafe.Pointer(h.curArena.base), size)
+			}
+			// Switch to the new space.
+			h.curArena.base = uintptr(av)
+			h.curArena.end = uintptr(av) + asize
+		}
+
+		// The memory just allocated counts as both released
+		// and idle, even though it's not yet backed by spans.
+		//
+		// The allocation is always aligned to the heap arena
+		// size which is always > physPageSize, so its safe to
+		// just add directly to heap_released. Coalescing, if
+		// possible, will also always be correct in terms of
+		// accounting, because s.base() must be a physical
+		// page boundary.
+		memstats.heap_released += uint64(asize)
+		memstats.heap_idle += uint64(asize)
+
+		// Recalculate nBase
+		nBase = round(h.curArena.base+ask, physPageSize)
+	}
+
+	// Grow into the current arena.
+	v := h.curArena.base
+	h.curArena.base = nBase
+	h.growAddSpan(unsafe.Pointer(v), nBase-v)
+	return true
+}
+
+// growAddSpan adds a free span when the heap grows into [v, v+size).
+// This memory must be in the Prepared state (not Ready).
+//
+// h must be locked.
+func (h *mheap) growAddSpan(v unsafe.Pointer, size uintptr) {
+	// Scavenge some pages to make up for the virtual memory space
+	// we just allocated, but only if we need to.
+	h.scavengeIfNeededLocked(size)
+
 	s := (*mspan)(h.spanalloc.alloc())
 	s.init(uintptr(v), size/pageSize)
 	h.setSpans(s.base(), s.npages, s)
 	s.state = mSpanFree
-	memstats.heap_idle += uint64(size)
-	// (*mheap).sysAlloc returns untouched/uncommitted memory.
+	// [v, v+size) is always in the Prepared state. The new span
+	// must be marked scavenged so the allocator transitions it to
+	// Ready when allocating from it.
 	s.scavenged = true
-	// s is always aligned to the heap arena size which is always > physPageSize,
-	// so its totally safe to just add directly to heap_released. Coalescing,
-	// if possible, will also always be correct in terms of accounting, because
-	// s.base() must be a physical page boundary.
-	memstats.heap_released += uint64(size)
+	// This span is both released and idle, but grow already
+	// updated both memstats.
 	h.coalesce(s)
 	h.free.insert(s)
-	return true
 }
 
 // Free the span back into the heap.
diff --git a/src/runtime/mstats.go b/src/runtime/mstats.go
index 421580eec3..09dbb26735 100644
--- a/src/runtime/mstats.go
+++ b/src/runtime/mstats.go
@@ -79,6 +79,8 @@ type mstats struct {
 
 	last_gc_nanotime uint64 // last gc (monotonic time)
 	tinyallocs       uint64 // number of tiny allocations that didn't cause actual allocation; not exported to go directly
+	last_next_gc     uint64 // next_gc for the previous GC
+	last_heap_inuse  uint64 // heap_inuse at mark termination of the previous GC
 
 	// triggerRatio is the heap growth ratio that triggers marking.
 	//
diff --git a/src/runtime/os_windows.go b/src/runtime/os_windows.go
index 074ae0f40d..1cd0932eae 100644
--- a/src/runtime/os_windows.go
+++ b/src/runtime/os_windows.go
@@ -49,6 +49,7 @@ const (
 //go:cgo_import_dynamic runtime._VirtualFree VirtualFree%3 "kernel32.dll"
 //go:cgo_import_dynamic runtime._VirtualQuery VirtualQuery%3 "kernel32.dll"
 //go:cgo_import_dynamic runtime._WaitForSingleObject WaitForSingleObject%2 "kernel32.dll"
+//go:cgo_import_dynamic runtime._WaitForMultipleObjects WaitForMultipleObjects%4 "kernel32.dll"
 //go:cgo_import_dynamic runtime._WriteConsoleW WriteConsoleW%5 "kernel32.dll"
 //go:cgo_import_dynamic runtime._WriteFile WriteFile%5 "kernel32.dll"
 
@@ -96,6 +97,7 @@ var (
 	_VirtualFree,
 	_VirtualQuery,
 	_WaitForSingleObject,
+	_WaitForMultipleObjects,
 	_WriteConsoleW,
 	_WriteFile,
 	_ stdFunction
@@ -139,7 +141,8 @@ func tstart_stdcall(newm *m)
 func ctrlhandler()
 
 type mOS struct {
-	waitsema uintptr // semaphore for parking on locks
+	waitsema   uintptr // semaphore for parking on locks
+	resumesema uintptr // semaphore to indicate suspend/resume
 }
 
 //go:linkname os_sigpipe os.sigpipe
@@ -258,6 +261,40 @@ func loadOptionalSyscalls() {
 	}
 }
 
+func monitorSuspendResume() {
+	const _DEVICE_NOTIFY_CALLBACK = 2
+	type _DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS struct {
+		callback uintptr
+		context  uintptr
+	}
+
+	powrprof := windowsLoadSystemLib([]byte("powrprof.dll\000"))
+	if powrprof == 0 {
+		return // Running on Windows 7, where we don't need it anyway.
+	}
+	powerRegisterSuspendResumeNotification := windowsFindfunc(powrprof, []byte("PowerRegisterSuspendResumeNotification\000"))
+	if powerRegisterSuspendResumeNotification == nil {
+		return // Running on Windows 7, where we don't need it anyway.
+	}
+	var fn interface{} = func(context uintptr, changeType uint32, setting uintptr) uintptr {
+		for mp := (*m)(atomic.Loadp(unsafe.Pointer(&allm))); mp != nil; mp = mp.alllink {
+			if mp.resumesema != 0 {
+				stdcall1(_SetEvent, mp.resumesema)
+			}
+		}
+		return 0
+	}
+	params := _DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS{
+		callback: compileCallback(*efaceOf(&fn), true),
+	}
+	handle := uintptr(0)
+	if stdcall3(powerRegisterSuspendResumeNotification, _DEVICE_NOTIFY_CALLBACK,
+		uintptr(unsafe.Pointer(&params)),
+		uintptr(unsafe.Pointer(&handle))) != 0 {
+		throw("PowerRegisterSuspendResumeNotification failure")
+	}
+}
+
 //go:nosplit
 func getLoadLibrary() uintptr {
 	return uintptr(unsafe.Pointer(_LoadLibraryW))
@@ -488,6 +525,10 @@ func goenvs() {
 	}
 
 	stdcall1(_FreeEnvironmentStringsW, uintptr(strings))
+
+	// We call this all the way here, late in init, so that malloc works
+	// for the callback function this generates.
+	monitorSuspendResume()
 }
 
 // exiting is set to non-zero when the process is exiting.
@@ -606,19 +647,32 @@ func semasleep(ns int64) int32 {
 		_WAIT_FAILED    = 0xFFFFFFFF
 	)
 
-	// store ms in ns to save stack space
+	var result uintptr
 	if ns < 0 {
-		ns = _INFINITE
+		result = stdcall2(_WaitForSingleObject, getg().m.waitsema, uintptr(_INFINITE))
 	} else {
-		ns = int64(timediv(ns, 1000000, nil))
-		if ns == 0 {
-			ns = 1
+		start := nanotime()
+		elapsed := int64(0)
+		for {
+			ms := int64(timediv(ns-elapsed, 1000000, nil))
+			if ms == 0 {
+				ms = 1
+			}
+			result = stdcall4(_WaitForMultipleObjects, 2,
+				uintptr(unsafe.Pointer(&[2]uintptr{getg().m.waitsema, getg().m.resumesema})),
+				0, uintptr(ms))
+			if result != _WAIT_OBJECT_0+1 {
+				// Not a suspend/resume event
+				break
+			}
+			elapsed = nanotime() - start
+			if elapsed >= ns {
+				return -1
+			}
 		}
 	}
-
-	result := stdcall2(_WaitForSingleObject, getg().m.waitsema, uintptr(ns))
 	switch result {
-	case _WAIT_OBJECT_0: //signaled
+	case _WAIT_OBJECT_0: // Signaled
 		return 0
 
 	case _WAIT_TIMEOUT:
@@ -667,6 +721,15 @@ func semacreate(mp *m) {
 			throw("runtime.semacreate")
 		})
 	}
+	mp.resumesema = stdcall4(_CreateEventA, 0, 0, 0, 0)
+	if mp.resumesema == 0 {
+		systemstack(func() {
+			print("runtime: createevent failed; errno=", getlasterror(), "\n")
+			throw("runtime.semacreate")
+		})
+		stdcall1(_CloseHandle, mp.waitsema)
+		mp.waitsema = 0
+	}
 }
 
 // May run with m.p==nil, so write barriers are not allowed. This
diff --git a/src/runtime/sys_darwin.go b/src/runtime/sys_darwin.go
index 376f76dbc5..a630d53a6e 100644
--- a/src/runtime/sys_darwin.go
+++ b/src/runtime/sys_darwin.go
@@ -60,7 +60,7 @@ func libcCall(fn, arg unsafe.Pointer) int32 {
 //go:nosplit
 //go:cgo_unsafe_args
 func syscall_syscall(fn, a1, a2, a3 uintptr) (r1, r2, err uintptr) {
-	entersyscallblock()
+	entersyscall()
 	libcCall(unsafe.Pointer(funcPC(syscall)), unsafe.Pointer(&fn))
 	exitsyscall()
 	return
@@ -71,7 +71,7 @@ func syscall()
 //go:nosplit
 //go:cgo_unsafe_args
 func syscall_syscall6(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr) {
-	entersyscallblock()
+	entersyscall()
 	libcCall(unsafe.Pointer(funcPC(syscall6)), unsafe.Pointer(&fn))
 	exitsyscall()
 	return
@@ -82,7 +82,7 @@ func syscall6()
 //go:nosplit
 //go:cgo_unsafe_args
 func syscall_syscall6X(fn, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2, err uintptr) {
-	entersyscallblock()
+	entersyscall()
 	libcCall(unsafe.Pointer(funcPC(syscall6X)), unsafe.Pointer(&fn))
 	exitsyscall()
 	return
@@ -93,7 +93,7 @@ func syscall6X()
 //go:nosplit
 //go:cgo_unsafe_args
 func syscall_syscallPtr(fn, a1, a2, a3 uintptr) (r1, r2, err uintptr) {
-	entersyscallblock()
+	entersyscall()
 	libcCall(unsafe.Pointer(funcPC(syscallPtr)), unsafe.Pointer(&fn))
 	exitsyscall()
 	return
diff --git a/src/runtime/syscall_windows.go b/src/runtime/syscall_windows.go
index 722a73d108..0e2fcfb02d 100644
--- a/src/runtime/syscall_windows.go
+++ b/src/runtime/syscall_windows.go
@@ -74,16 +74,18 @@ func compileCallback(fn eface, cleanstack bool) (code uintptr) {
 		argsize += uintptrSize
 	}
 
-	lock(&cbs.lock)
-	defer unlock(&cbs.lock)
+	lock(&cbs.lock) // We don't unlock this in a defer because this is used from the system stack.
 
 	n := cbs.n
 	for i := 0; i < n; i++ {
 		if cbs.ctxt[i].gobody == fn.data && cbs.ctxt[i].isCleanstack() == cleanstack {
-			return callbackasmAddr(i)
+			r := callbackasmAddr(i)
+			unlock(&cbs.lock)
+			return r
 		}
 	}
 	if n >= cb_max {
+		unlock(&cbs.lock)
 		throw("too many callback functions")
 	}
 
@@ -99,7 +101,9 @@ func compileCallback(fn eface, cleanstack bool) (code uintptr) {
 	cbs.ctxt[n] = c
 	cbs.n++
 
-	return callbackasmAddr(n)
+	r := callbackasmAddr(n)
+	unlock(&cbs.lock)
+	return r
 }
 
 const _LOAD_LIBRARY_SEARCH_SYSTEM32 = 0x00000800
diff --git a/src/syscall/mksyscall_windows.go b/src/syscall/mksyscall_windows.go
index ee2123f939..d66bf7865f 100644
--- a/src/syscall/mksyscall_windows.go
+++ b/src/syscall/mksyscall_windows.go
@@ -4,897 +4,23 @@
 
 // +build ignore
 
-/*
-mksyscall_windows generates windows system call bodies
-
-It parses all files specified on command line containing function
-prototypes (like syscall_windows.go) and prints system call bodies
-to standard output.
-
-The prototypes are marked by lines beginning with "//sys" and read
-like func declarations if //sys is replaced by func, but:
-
-* The parameter lists must give a name for each argument. This
-  includes return parameters.
-
-* The parameter lists must give a type for each argument:
-  the (x, y, z int) shorthand is not allowed.
-
-* If the return parameter is an error number, it must be named err.
-
-* If go func name needs to be different from its winapi dll name,
-  the winapi name could be specified at the end, after "=" sign, like
-  //sys LoadLibrary(libname string) (handle uint32, err error) = LoadLibraryA
-
-* Each function that returns err needs to supply a condition, that
-  return value of winapi will be tested against to detect failure.
-  This would set err to windows "last-error", otherwise it will be nil.
-  The value can be provided at end of //sys declaration, like
-  //sys LoadLibrary(libname string) (handle uint32, err error) [failretval==-1] = LoadLibraryA
-  and is [failretval==0] by default.
-
-Usage:
-	mksyscall_windows [flags] [path ...]
-
-The flags are:
-	-output
-		Specify output file name (outputs to console if blank).
-	-trace
-		Generate print statement after every syscall.
-*/
 package main
 
 import (
-	"bufio"
-	"bytes"
-	"errors"
-	"flag"
-	"fmt"
-	"go/format"
-	"go/parser"
-	"go/token"
-	"io"
-	"io/ioutil"
-	"log"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"runtime"
-	"sort"
-	"strconv"
-	"strings"
-	"text/template"
-)
-
-var (
-	filename       = flag.String("output", "", "output file name (standard output if omitted)")
-	printTraceFlag = flag.Bool("trace", false, "generate print statement after every syscall")
-	systemDLL      = flag.Bool("systemdll", true, "whether all DLLs should be loaded from the Windows system directory")
 )
 
-func trim(s string) string {
-	return strings.Trim(s, " \t")
-}
-
-var packageName string
-
-func packagename() string {
-	return packageName
-}
-
-func syscalldot() string {
-	if packageName == "syscall" {
-		return ""
-	}
-	return "syscall."
-}
-
-// Param is function parameter
-type Param struct {
-	Name      string
-	Type      string
-	fn        *Fn
-	tmpVarIdx int
-}
-
-// tmpVar returns temp variable name that will be used to represent p during syscall.
-func (p *Param) tmpVar() string {
-	if p.tmpVarIdx < 0 {
-		p.tmpVarIdx = p.fn.curTmpVarIdx
-		p.fn.curTmpVarIdx++
-	}
-	return fmt.Sprintf("_p%d", p.tmpVarIdx)
-}
-
-// BoolTmpVarCode returns source code for bool temp variable.
-func (p *Param) BoolTmpVarCode() string {
-	const code = `var %s uint32
-	if %s {
-		%s = 1
-	} else {
-		%s = 0
-	}`
-	tmp := p.tmpVar()
-	return fmt.Sprintf(code, tmp, p.Name, tmp, tmp)
-}
-
-// SliceTmpVarCode returns source code for slice temp variable.
-func (p *Param) SliceTmpVarCode() string {
-	const code = `var %s *%s
-	if len(%s) > 0 {
-		%s = &%s[0]
-	}`
-	tmp := p.tmpVar()
-	return fmt.Sprintf(code, tmp, p.Type[2:], p.Name, tmp, p.Name)
-}
-
-// StringTmpVarCode returns source code for string temp variable.
-func (p *Param) StringTmpVarCode() string {
-	errvar := p.fn.Rets.ErrorVarName()
-	if errvar == "" {
-		errvar = "_"
-	}
-	tmp := p.tmpVar()
-	const code = `var %s %s
-	%s, %s = %s(%s)`
-	s := fmt.Sprintf(code, tmp, p.fn.StrconvType(), tmp, errvar, p.fn.StrconvFunc(), p.Name)
-	if errvar == "-" {
-		return s
-	}
-	const morecode = `
-	if %s != nil {
-		return
-	}`
-	return s + fmt.Sprintf(morecode, errvar)
-}
-
-// TmpVarCode returns source code for temp variable.
-func (p *Param) TmpVarCode() string {
-	switch {
-	case p.Type == "bool":
-		return p.BoolTmpVarCode()
-	case strings.HasPrefix(p.Type, "[]"):
-		return p.SliceTmpVarCode()
-	default:
-		return ""
-	}
-}
-
-// TmpVarHelperCode returns source code for helper's temp variable.
-func (p *Param) TmpVarHelperCode() string {
-	if p.Type != "string" {
-		return ""
-	}
-	return p.StringTmpVarCode()
-}
-
-// SyscallArgList returns source code fragments representing p parameter
-// in syscall. Slices are translated into 2 syscall parameters: pointer to
-// the first element and length.
-func (p *Param) SyscallArgList() []string {
-	t := p.HelperType()
-	var s string
-	switch {
-	case t[0] == '*':
-		s = fmt.Sprintf("unsafe.Pointer(%s)", p.Name)
-	case t == "bool":
-		s = p.tmpVar()
-	case strings.HasPrefix(t, "[]"):
-		return []string{
-			fmt.Sprintf("uintptr(unsafe.Pointer(%s))", p.tmpVar()),
-			fmt.Sprintf("uintptr(len(%s))", p.Name),
-		}
-	default:
-		s = p.Name
-	}
-	return []string{fmt.Sprintf("uintptr(%s)", s)}
-}
-
-// IsError determines if p parameter is used to return error.
-func (p *Param) IsError() bool {
-	return p.Name == "err" && p.Type == "error"
-}
-
-// HelperType returns type of parameter p used in helper function.
-func (p *Param) HelperType() string {
-	if p.Type == "string" {
-		return p.fn.StrconvType()
-	}
-	return p.Type
-}
-
-// join concatenates parameters ps into a string with sep separator.
-// Each parameter is converted into string by applying fn to it
-// before conversion.
-func join(ps []*Param, fn func(*Param) string, sep string) string {
-	if len(ps) == 0 {
-		return ""
-	}
-	a := make([]string, 0)
-	for _, p := range ps {
-		a = append(a, fn(p))
-	}
-	return strings.Join(a, sep)
-}
-
-// Rets describes function return parameters.
-type Rets struct {
-	Name         string
-	Type         string
-	ReturnsError bool
-	FailCond     string
-}
-
-// ErrorVarName returns error variable name for r.
-func (r *Rets) ErrorVarName() string {
-	if r.ReturnsError {
-		return "err"
-	}
-	if r.Type == "error" {
-		return r.Name
-	}
-	return ""
-}
-
-// ToParams converts r into slice of *Param.
-func (r *Rets) ToParams() []*Param {
-	ps := make([]*Param, 0)
-	if len(r.Name) > 0 {
-		ps = append(ps, &Param{Name: r.Name, Type: r.Type})
-	}
-	if r.ReturnsError {
-		ps = append(ps, &Param{Name: "err", Type: "error"})
-	}
-	return ps
-}
-
-// List returns source code of syscall return parameters.
-func (r *Rets) List() string {
-	s := join(r.ToParams(), func(p *Param) string { return p.Name + " " + p.Type }, ", ")
-	if len(s) > 0 {
-		s = "(" + s + ")"
-	}
-	return s
-}
-
-// PrintList returns source code of trace printing part correspondent
-// to syscall return values.
-func (r *Rets) PrintList() string {
-	return join(r.ToParams(), func(p *Param) string { return fmt.Sprintf(`"%s=", %s, `, p.Name, p.Name) }, `", ", `)
-}
-
-// SetReturnValuesCode returns source code that accepts syscall return values.
-func (r *Rets) SetReturnValuesCode() string {
-	if r.Name == "" && !r.ReturnsError {
-		return ""
-	}
-	retvar := "r0"
-	if r.Name == "" {
-		retvar = "r1"
-	}
-	errvar := "_"
-	if r.ReturnsError {
-		errvar = "e1"
-	}
-	return fmt.Sprintf("%s, _, %s := ", retvar, errvar)
-}
-
-func (r *Rets) useLongHandleErrorCode(retvar string) string {
-	const code = `if %s {
-		if e1 != 0 {
-			err = errnoErr(e1)
-		} else {
-			err = %sEINVAL
-		}
-	}`
-	cond := retvar + " == 0"
-	if r.FailCond != "" {
-		cond = strings.Replace(r.FailCond, "failretval", retvar, 1)
-	}
-	return fmt.Sprintf(code, cond, syscalldot())
-}
-
-// SetErrorCode returns source code that sets return parameters.
-func (r *Rets) SetErrorCode() string {
-	const code = `if r0 != 0 {
-		%s = %sErrno(r0)
-	}`
-	if r.Name == "" && !r.ReturnsError {
-		return ""
-	}
-	if r.Name == "" {
-		return r.useLongHandleErrorCode("r1")
-	}
-	if r.Type == "error" {
-		return fmt.Sprintf(code, r.Name, syscalldot())
-	}
-	s := ""
-	switch {
-	case r.Type[0] == '*':
-		s = fmt.Sprintf("%s = (%s)(unsafe.Pointer(r0))", r.Name, r.Type)
-	case r.Type == "bool":
-		s = fmt.Sprintf("%s = r0 != 0", r.Name)
-	default:
-		s = fmt.Sprintf("%s = %s(r0)", r.Name, r.Type)
-	}
-	if !r.ReturnsError {
-		return s
-	}
-	return s + "\n\t" + r.useLongHandleErrorCode(r.Name)
-}
-
-// Fn describes syscall function.
-type Fn struct {
-	Name        string
-	Params      []*Param
-	Rets        *Rets
-	PrintTrace  bool
-	dllname     string
-	dllfuncname string
-	src         string
-	// TODO: get rid of this field and just use parameter index instead
-	curTmpVarIdx int // insure tmp variables have uniq names
-}
-
-// extractParams parses s to extract function parameters.
-func extractParams(s string, f *Fn) ([]*Param, error) {
-	s = trim(s)
-	if s == "" {
-		return nil, nil
-	}
-	a := strings.Split(s, ",")
-	ps := make([]*Param, len(a))
-	for i := range ps {
-		s2 := trim(a[i])
-		b := strings.Split(s2, " ")
-		if len(b) != 2 {
-			b = strings.Split(s2, "\t")
-			if len(b) != 2 {
-				return nil, errors.New("Could not extract function parameter from \"" + s2 + "\"")
-			}
-		}
-		ps[i] = &Param{
-			Name:      trim(b[0]),
-			Type:      trim(b[1]),
-			fn:        f,
-			tmpVarIdx: -1,
-		}
-	}
-	return ps, nil
-}
-
-// extractSection extracts text out of string s starting after start
-// and ending just before end. found return value will indicate success,
-// and prefix, body and suffix will contain correspondent parts of string s.
-func extractSection(s string, start, end rune) (prefix, body, suffix string, found bool) {
-	s = trim(s)
-	if strings.HasPrefix(s, string(start)) {
-		// no prefix
-		body = s[1:]
-	} else {
-		a := strings.SplitN(s, string(start), 2)
-		if len(a) != 2 {
-			return "", "", s, false
-		}
-		prefix = a[0]
-		body = a[1]
-	}
-	a := strings.SplitN(body, string(end), 2)
-	if len(a) != 2 {
-		return "", "", "", false
-	}
-	return prefix, a[0], a[1], true
-}
-
-// newFn parses string s and return created function Fn.
-func newFn(s string) (*Fn, error) {
-	s = trim(s)
-	f := &Fn{
-		Rets:       &Rets{},
-		src:        s,
-		PrintTrace: *printTraceFlag,
-	}
-	// function name and args
-	prefix, body, s, found := extractSection(s, '(', ')')
-	if !found || prefix == "" {
-		return nil, errors.New("Could not extract function name and parameters from \"" + f.src + "\"")
-	}
-	f.Name = prefix
-	var err error
-	f.Params, err = extractParams(body, f)
-	if err != nil {
-		return nil, err
-	}
-	// return values
-	_, body, s, found = extractSection(s, '(', ')')
-	if found {
-		r, err := extractParams(body, f)
-		if err != nil {
-			return nil, err
-		}
-		switch len(r) {
-		case 0:
-		case 1:
-			if r[0].IsError() {
-				f.Rets.ReturnsError = true
-			} else {
-				f.Rets.Name = r[0].Name
-				f.Rets.Type = r[0].Type
-			}
-		case 2:
-			if !r[1].IsError() {
-				return nil, errors.New("Only last windows error is allowed as second return value in \"" + f.src + "\"")
-			}
-			f.Rets.ReturnsError = true
-			f.Rets.Name = r[0].Name
-			f.Rets.Type = r[0].Type
-		default:
-			return nil, errors.New("Too many return values in \"" + f.src + "\"")
-		}
-	}
-	// fail condition
-	_, body, s, found = extractSection(s, '[', ']')
-	if found {
-		f.Rets.FailCond = body
-	}
-	// dll and dll function names
-	s = trim(s)
-	if s == "" {
-		return f, nil
-	}
-	if !strings.HasPrefix(s, "=") {
-		return nil, errors.New("Could not extract dll name from \"" + f.src + "\"")
-	}
-	s = trim(s[1:])
-	a := strings.Split(s, ".")
-	switch len(a) {
-	case 1:
-		f.dllfuncname = a[0]
-	case 2:
-		f.dllname = a[0]
-		f.dllfuncname = a[1]
-	default:
-		return nil, errors.New("Could not extract dll name from \"" + f.src + "\"")
-	}
-	return f, nil
-}
-
-// DLLName returns DLL name for function f.
-func (f *Fn) DLLName() string {
-	if f.dllname == "" {
-		return "kernel32"
-	}
-	return f.dllname
-}
-
-// DLLName returns DLL function name for function f.
-func (f *Fn) DLLFuncName() string {
-	if f.dllfuncname == "" {
-		return f.Name
-	}
-	return f.dllfuncname
-}
-
-// ParamList returns source code for function f parameters.
-func (f *Fn) ParamList() string {
-	return join(f.Params, func(p *Param) string { return p.Name + " " + p.Type }, ", ")
-}
-
-// HelperParamList returns source code for helper function f parameters.
-func (f *Fn) HelperParamList() string {
-	return join(f.Params, func(p *Param) string { return p.Name + " " + p.HelperType() }, ", ")
-}
-
-// ParamPrintList returns source code of trace printing part correspondent
-// to syscall input parameters.
-func (f *Fn) ParamPrintList() string {
-	return join(f.Params, func(p *Param) string { return fmt.Sprintf(`"%s=", %s, `, p.Name, p.Name) }, `", ", `)
-}
-
-// ParamCount return number of syscall parameters for function f.
-func (f *Fn) ParamCount() int {
-	n := 0
-	for _, p := range f.Params {
-		n += len(p.SyscallArgList())
-	}
-	return n
-}
-
-// SyscallParamCount determines which version of Syscall/Syscall6/Syscall9/...
-// to use. It returns parameter count for correspondent SyscallX function.
-func (f *Fn) SyscallParamCount() int {
-	n := f.ParamCount()
-	switch {
-	case n <= 3:
-		return 3
-	case n <= 6:
-		return 6
-	case n <= 9:
-		return 9
-	case n <= 12:
-		return 12
-	case n <= 15:
-		return 15
-	default:
-		panic("too many arguments to system call")
-	}
-}
-
-// Syscall determines which SyscallX function to use for function f.
-func (f *Fn) Syscall() string {
-	c := f.SyscallParamCount()
-	if c == 3 {
-		return syscalldot() + "Syscall"
-	}
-	return syscalldot() + "Syscall" + strconv.Itoa(c)
-}
-
-// SyscallParamList returns source code for SyscallX parameters for function f.
-func (f *Fn) SyscallParamList() string {
-	a := make([]string, 0)
-	for _, p := range f.Params {
-		a = append(a, p.SyscallArgList()...)
-	}
-	for len(a) < f.SyscallParamCount() {
-		a = append(a, "0")
-	}
-	return strings.Join(a, ", ")
-}
-
-// HelperCallParamList returns source code of call into function f helper.
-func (f *Fn) HelperCallParamList() string {
-	a := make([]string, 0, len(f.Params))
-	for _, p := range f.Params {
-		s := p.Name
-		if p.Type == "string" {
-			s = p.tmpVar()
-		}
-		a = append(a, s)
-	}
-	return strings.Join(a, ", ")
-}
-
-// IsUTF16 is true, if f is W (utf16) function. It is false
-// for all A (ascii) functions.
-func (f *Fn) IsUTF16() bool {
-	s := f.DLLFuncName()
-	return s[len(s)-1] == 'W'
-}
-
-// StrconvFunc returns name of Go string to OS string function for f.
-func (f *Fn) StrconvFunc() string {
-	if f.IsUTF16() {
-		return syscalldot() + "UTF16PtrFromString"
-	}
-	return syscalldot() + "BytePtrFromString"
-}
-
-// StrconvType returns Go type name used for OS string for f.
-func (f *Fn) StrconvType() string {
-	if f.IsUTF16() {
-		return "*uint16"
-	}
-	return "*byte"
-}
-
-// HasStringParam is true, if f has at least one string parameter.
-// Otherwise it is false.
-func (f *Fn) HasStringParam() bool {
-	for _, p := range f.Params {
-		if p.Type == "string" {
-			return true
-		}
-	}
-	return false
-}
-
-// HelperName returns name of function f helper.
-func (f *Fn) HelperName() string {
-	if !f.HasStringParam() {
-		return f.Name
-	}
-	return "_" + f.Name
-}
-
-// Source files and functions.
-type Source struct {
-	Funcs           []*Fn
-	Files           []string
-	StdLibImports   []string
-	ExternalImports []string
-}
-
-func (src *Source) Import(pkg string) {
-	src.StdLibImports = append(src.StdLibImports, pkg)
-	sort.Strings(src.StdLibImports)
-}
-
-func (src *Source) ExternalImport(pkg string) {
-	src.ExternalImports = append(src.ExternalImports, pkg)
-	sort.Strings(src.ExternalImports)
-}
-
-// ParseFiles parses files listed in fs and extracts all syscall
-// functions listed in sys comments. It returns source files
-// and functions collection *Source if successful.
-func ParseFiles(fs []string) (*Source, error) {
-	src := &Source{
-		Funcs: make([]*Fn, 0),
-		Files: make([]string, 0),
-		StdLibImports: []string{
-			"unsafe",
-		},
-		ExternalImports: make([]string, 0),
-	}
-	for _, file := range fs {
-		if err := src.ParseFile(file); err != nil {
-			return nil, err
-		}
-	}
-	return src, nil
-}
-
-// DLLs return dll names for a source set src.
-func (src *Source) DLLs() []string {
-	uniq := make(map[string]bool)
-	r := make([]string, 0)
-	for _, f := range src.Funcs {
-		name := f.DLLName()
-		if _, found := uniq[name]; !found {
-			uniq[name] = true
-			r = append(r, name)
-		}
-	}
-	return r
-}
-
-// ParseFile adds additional file path to a source set src.
-func (src *Source) ParseFile(path string) error {
-	file, err := os.Open(path)
-	if err != nil {
-		return err
-	}
-	defer file.Close()
-
-	s := bufio.NewScanner(file)
-	for s.Scan() {
-		t := trim(s.Text())
-		if len(t) < 7 {
-			continue
-		}
-		if !strings.HasPrefix(t, "//sys") {
-			continue
-		}
-		t = t[5:]
-		if !(t[0] == ' ' || t[0] == '\t') {
-			continue
-		}
-		f, err := newFn(t[1:])
-		if err != nil {
-			return err
-		}
-		src.Funcs = append(src.Funcs, f)
-	}
-	if err := s.Err(); err != nil {
-		return err
-	}
-	src.Files = append(src.Files, path)
-
-	// get package name
-	fset := token.NewFileSet()
-	_, err = file.Seek(0, 0)
-	if err != nil {
-		return err
-	}
-	pkg, err := parser.ParseFile(fset, "", file, parser.PackageClauseOnly)
-	if err != nil {
-		return err
-	}
-	packageName = pkg.Name.Name
-
-	return nil
-}
-
-// IsStdRepo reports whether src is part of standard library.
-func (src *Source) IsStdRepo() (bool, error) {
-	if len(src.Files) == 0 {
-		return false, errors.New("no input files provided")
-	}
-	abspath, err := filepath.Abs(src.Files[0])
-	if err != nil {
-		return false, err
-	}
-	goroot := runtime.GOROOT()
-	if runtime.GOOS == "windows" {
-		abspath = strings.ToLower(abspath)
-		goroot = strings.ToLower(goroot)
-	}
-	sep := string(os.PathSeparator)
-	if !strings.HasSuffix(goroot, sep) {
-		goroot += sep
-	}
-	return strings.HasPrefix(abspath, goroot), nil
-}
-
-// Generate output source file from a source set src.
-func (src *Source) Generate(w io.Writer) error {
-	const (
-		pkgStd         = iota // any package in std library
-		pkgXSysWindows        // x/sys/windows package
-		pkgOther
-	)
-	isStdRepo, err := src.IsStdRepo()
-	if err != nil {
-		return err
-	}
-	var pkgtype int
-	switch {
-	case isStdRepo:
-		pkgtype = pkgStd
-	case packageName == "windows":
-		// TODO: this needs better logic than just using package name
-		pkgtype = pkgXSysWindows
-	default:
-		pkgtype = pkgOther
-	}
-	if *systemDLL {
-		switch pkgtype {
-		case pkgStd:
-			src.Import("internal/syscall/windows/sysdll")
-		case pkgXSysWindows:
-		default:
-			src.ExternalImport("golang.org/x/sys/windows")
-		}
-	}
-	if packageName != "syscall" {
-		src.Import("syscall")
-	}
-	funcMap := template.FuncMap{
-		"packagename": packagename,
-		"syscalldot":  syscalldot,
-		"newlazydll": func(dll string) string {
-			arg := "\"" + dll + ".dll\""
-			if !*systemDLL {
-				return syscalldot() + "NewLazyDLL(" + arg + ")"
-			}
-			switch pkgtype {
-			case pkgStd:
-				return syscalldot() + "NewLazyDLL(sysdll.Add(" + arg + "))"
-			case pkgXSysWindows:
-				return "NewLazySystemDLL(" + arg + ")"
-			default:
-				return "windows.NewLazySystemDLL(" + arg + ")"
-			}
-		},
-	}
-	t := template.Must(template.New("main").Funcs(funcMap).Parse(srcTemplate))
-	err = t.Execute(w, src)
-	if err != nil {
-		return errors.New("Failed to execute template: " + err.Error())
-	}
-	return nil
-}
-
-func usage() {
-	fmt.Fprintf(os.Stderr, "usage: mksyscall_windows [flags] [path ...]\n")
-	flag.PrintDefaults()
-	os.Exit(1)
-}
-
 func main() {
-	flag.Usage = usage
-	flag.Parse()
-	if len(flag.Args()) <= 0 {
-		fmt.Fprintf(os.Stderr, "no files to parse provided\n")
-		usage()
-	}
-
-	src, err := ParseFiles(flag.Args())
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	var buf bytes.Buffer
-	if err := src.Generate(&buf); err != nil {
-		log.Fatal(err)
-	}
-
-	data, err := format.Source(buf.Bytes())
+	os.Stderr.WriteString("WARNING: Please switch from using:\n    go run $GOROOT/src/syscall/mksyscall_windows.go\nto using:\n    go run golang.org/x/sys/windows/mkwinsyscall\n")
+	args := append([]string{"run", "golang.org/x/sys/windows/mkwinsyscall"}, os.Args[1:]...)
+	cmd := exec.Command(filepath.Join(runtime.GOROOT(), "bin", "go"), args...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	err := cmd.Run()
 	if err != nil {
-		log.Fatal(err)
-	}
-	if *filename == "" {
-		_, err = os.Stdout.Write(data)
-	} else {
-		err = ioutil.WriteFile(*filename, data, 0644)
-	}
-	if err != nil {
-		log.Fatal(err)
+		os.Exit(1)
 	}
 }
-
-// TODO: use println instead to print in the following template
-const srcTemplate = `
-
-{{define "main"}}// Code generated by 'go generate'; DO NOT EDIT.
-
-package {{packagename}}
-
-import (
-{{range .StdLibImports}}"{{.}}"
-{{end}}
-
-{{range .ExternalImports}}"{{.}}"
-{{end}}
-)
-
-var _ unsafe.Pointer
-
-// Do the interface allocations only once for common
-// Errno values.
-const (
-	errnoERROR_IO_PENDING = 997
-)
-
-var (
-	errERROR_IO_PENDING error = {{syscalldot}}Errno(errnoERROR_IO_PENDING)
-)
-
-// errnoErr returns common boxed Errno values, to prevent
-// allocations at runtime.
-func errnoErr(e {{syscalldot}}Errno) error {
-	switch e {
-	case 0:
-		return nil
-	case errnoERROR_IO_PENDING:
-		return errERROR_IO_PENDING
-	}
-	// TODO: add more here, after collecting data on the common
-	// error values see on Windows. (perhaps when running
-	// all.bat?)
-	return e
-}
-
-var (
-{{template "dlls" .}}
-{{template "funcnames" .}})
-{{range .Funcs}}{{if .HasStringParam}}{{template "helperbody" .}}{{end}}{{template "funcbody" .}}{{end}}
-{{end}}
-
-{{/* help functions */}}
-
-{{define "dlls"}}{{range .DLLs}}	mod{{.}} = {{newlazydll .}}
-{{end}}{{end}}
-
-{{define "funcnames"}}{{range .Funcs}}	proc{{.DLLFuncName}} = mod{{.DLLName}}.NewProc("{{.DLLFuncName}}")
-{{end}}{{end}}
-
-{{define "helperbody"}}
-func {{.Name}}({{.ParamList}}) {{template "results" .}}{
-{{template "helpertmpvars" .}}	return {{.HelperName}}({{.HelperCallParamList}})
-}
-{{end}}
-
-{{define "funcbody"}}
-func {{.HelperName}}({{.HelperParamList}}) {{template "results" .}}{
-{{template "tmpvars" .}}	{{template "syscall" .}}
-{{template "seterror" .}}{{template "printtrace" .}}	return
-}
-{{end}}
-
-{{define "helpertmpvars"}}{{range .Params}}{{if .TmpVarHelperCode}}	{{.TmpVarHelperCode}}
-{{end}}{{end}}{{end}}
-
-{{define "tmpvars"}}{{range .Params}}{{if .TmpVarCode}}	{{.TmpVarCode}}
-{{end}}{{end}}{{end}}
-
-{{define "results"}}{{if .Rets.List}}{{.Rets.List}} {{end}}{{end}}
-
-{{define "syscall"}}{{.Rets.SetReturnValuesCode}}{{.Syscall}}(proc{{.DLLFuncName}}.Addr(), {{.ParamCount}}, {{.SyscallParamList}}){{end}}
-
-{{define "seterror"}}{{if .Rets.SetErrorCode}}	{{.Rets.SetErrorCode}}
-{{end}}{{end}}
-
-{{define "printtrace"}}{{if .PrintTrace}}	print("SYSCALL: {{.Name}}(", {{.ParamPrintList}}") (", {{.Rets.PrintList}}")\n")
-{{end}}{{end}}
-
-`
diff --git a/src/syscall/syscall.go b/src/syscall/syscall.go
index e02fc502c7..980ef9d27f 100644
--- a/src/syscall/syscall.go
+++ b/src/syscall/syscall.go
@@ -26,7 +26,7 @@
 //
 package syscall
 
-//go:generate go run mksyscall_windows.go -systemdll -output zsyscall_windows.go syscall_windows.go security_windows.go
+//go:generate go run golang.org/x/sys/windows/mkwinsyscall -systemdll -output zsyscall_windows.go syscall_windows.go security_windows.go
 
 // StringByteSlice converts a string to a NUL-terminated []byte,
 // If s contains a NUL byte this function panics instead of
diff --git a/src/syscall/syscall_darwin.go b/src/syscall/syscall_darwin.go
index 7d795ee4d3..2efcf3bea9 100644
--- a/src/syscall/syscall_darwin.go
+++ b/src/syscall/syscall_darwin.go
@@ -337,7 +337,6 @@ func Kill(pid int, signum Signal) (err error) { return kill(pid, int(signum), 1)
 //sysnb ioctlPtr(fd int, req uint, arg unsafe.Pointer) (err error) = SYS_ioctl
 //sysnb execve(path *byte, argv **byte, envp **byte) (err error)
 //sysnb exit(res int) (err error)
-//sys	sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error)
 //sys	fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) = SYS_fcntl
 //sys   unlinkat(fd int, path string, flags int) (err error)
 //sys   openat(fd int, path string, flags int, perm uint32) (fdret int, err error)
diff --git a/src/syscall/syscall_darwin_386.go b/src/syscall/syscall_darwin_386.go
index 8c5b82da55..46714bab57 100644
--- a/src/syscall/syscall_darwin_386.go
+++ b/src/syscall/syscall_darwin_386.go
@@ -22,6 +22,7 @@ func setTimeval(sec, usec int64) Timeval {
 //sys	Statfs(path string, stat *Statfs_t) (err error) = SYS_statfs64
 //sys   fstatat(fd int, path string, stat *Stat_t, flags int) (err error) = SYS_fstatat64
 //sys   ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
+//sys   sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error)
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Ident = uint32(fd)
diff --git a/src/syscall/syscall_darwin_amd64.go b/src/syscall/syscall_darwin_amd64.go
index 23a4e5f996..43506e4531 100644
--- a/src/syscall/syscall_darwin_amd64.go
+++ b/src/syscall/syscall_darwin_amd64.go
@@ -22,6 +22,7 @@ func setTimeval(sec, usec int64) Timeval {
 //sys	Statfs(path string, stat *Statfs_t) (err error) = SYS_statfs64
 //sys   fstatat(fd int, path string, stat *Stat_t, flags int) (err error) = SYS_fstatat64
 //sys   ptrace(request int, pid int, addr uintptr, data uintptr) (err error)
+//sys   sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error)
 
 func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Ident = uint64(fd)
diff --git a/src/syscall/syscall_darwin_arm.go b/src/syscall/syscall_darwin_arm.go
index 7f39cf4003..4ca2e300e4 100644
--- a/src/syscall/syscall_darwin_arm.go
+++ b/src/syscall/syscall_darwin_arm.go
@@ -29,6 +29,10 @@ func ptrace(request int, pid int, addr uintptr, data uintptr) error {
 	return ENOTSUP
 }
 
+func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) error {
+	return ENOTSUP
+}
+
 func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Ident = uint32(fd)
 	k.Filter = int16(mode)
diff --git a/src/syscall/syscall_darwin_arm64.go b/src/syscall/syscall_darwin_arm64.go
index bd110f2e7f..fde48f3596 100644
--- a/src/syscall/syscall_darwin_arm64.go
+++ b/src/syscall/syscall_darwin_arm64.go
@@ -29,6 +29,10 @@ func ptrace(request int, pid int, addr uintptr, data uintptr) error {
 	return ENOTSUP
 }
 
+func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) error {
+	return ENOTSUP
+}
+
 func SetKevent(k *Kevent_t, fd, mode, flags int) {
 	k.Ident = uint64(fd)
 	k.Filter = int16(mode)
diff --git a/src/syscall/zsyscall_darwin_386.go b/src/syscall/zsyscall_darwin_386.go
index 2c3b15f5f9..0ffc692116 100644
--- a/src/syscall/zsyscall_darwin_386.go
+++ b/src/syscall/zsyscall_darwin_386.go
@@ -1870,27 +1870,6 @@ func libc_exit_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) {
-	var _p0 unsafe.Pointer
-	if len(mib) > 0 {
-		_p0 = unsafe.Pointer(&mib[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-func libc_sysctl_trampoline()
-
-//go:linkname libc_sysctl libc_sysctl
-//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 	r0, _, e1 := syscall(funcPC(libc_fcntl_trampoline), uintptr(fd), uintptr(cmd), uintptr(arg))
 	val = int(r0)
@@ -2081,3 +2060,24 @@ func libc_ptrace_trampoline()
 
 //go:linkname libc_ptrace libc_ptrace
 //go:cgo_import_dynamic libc_ptrace ptrace "/usr/lib/libSystem.B.dylib"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) {
+	var _p0 unsafe.Pointer
+	if len(mib) > 0 {
+		_p0 = unsafe.Pointer(&mib[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_sysctl_trampoline()
+
+//go:linkname libc_sysctl libc_sysctl
+//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"
diff --git a/src/syscall/zsyscall_darwin_386.s b/src/syscall/zsyscall_darwin_386.s
index d84b46229e..0dec5baa22 100644
--- a/src/syscall/zsyscall_darwin_386.s
+++ b/src/syscall/zsyscall_darwin_386.s
@@ -229,8 +229,6 @@ TEXT ·libc_execve_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_execve(SB)
 TEXT ·libc_exit_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_exit(SB)
-TEXT ·libc_sysctl_trampoline(SB),NOSPLIT,$0-0
-	JMP	libc_sysctl(SB)
 TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unlinkat(SB)
 TEXT ·libc_openat_trampoline(SB),NOSPLIT,$0-0
@@ -251,3 +249,5 @@ TEXT ·libc_fstatat64_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_fstatat64(SB)
 TEXT ·libc_ptrace_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_ptrace(SB)
+TEXT ·libc_sysctl_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_sysctl(SB)
diff --git a/src/syscall/zsyscall_darwin_amd64.go b/src/syscall/zsyscall_darwin_amd64.go
index 83214de2fb..942152ae39 100644
--- a/src/syscall/zsyscall_darwin_amd64.go
+++ b/src/syscall/zsyscall_darwin_amd64.go
@@ -1870,27 +1870,6 @@ func libc_exit_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) {
-	var _p0 unsafe.Pointer
-	if len(mib) > 0 {
-		_p0 = unsafe.Pointer(&mib[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-func libc_sysctl_trampoline()
-
-//go:linkname libc_sysctl libc_sysctl
-//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 	r0, _, e1 := syscall(funcPC(libc_fcntl_trampoline), uintptr(fd), uintptr(cmd), uintptr(arg))
 	val = int(r0)
@@ -2081,3 +2060,24 @@ func libc_ptrace_trampoline()
 
 //go:linkname libc_ptrace libc_ptrace
 //go:cgo_import_dynamic libc_ptrace ptrace "/usr/lib/libSystem.B.dylib"
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
+func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) {
+	var _p0 unsafe.Pointer
+	if len(mib) > 0 {
+		_p0 = unsafe.Pointer(&mib[0])
+	} else {
+		_p0 = unsafe.Pointer(&_zero)
+	}
+	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+func libc_sysctl_trampoline()
+
+//go:linkname libc_sysctl libc_sysctl
+//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"
diff --git a/src/syscall/zsyscall_darwin_amd64.s b/src/syscall/zsyscall_darwin_amd64.s
index 23ddbe06c0..fcb7f9c291 100644
--- a/src/syscall/zsyscall_darwin_amd64.s
+++ b/src/syscall/zsyscall_darwin_amd64.s
@@ -229,8 +229,6 @@ TEXT ·libc_execve_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_execve(SB)
 TEXT ·libc_exit_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_exit(SB)
-TEXT ·libc_sysctl_trampoline(SB),NOSPLIT,$0-0
-	JMP	libc_sysctl(SB)
 TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unlinkat(SB)
 TEXT ·libc_openat_trampoline(SB),NOSPLIT,$0-0
@@ -251,3 +249,5 @@ TEXT ·libc_fstatat64_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_fstatat64(SB)
 TEXT ·libc_ptrace_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_ptrace(SB)
+TEXT ·libc_sysctl_trampoline(SB),NOSPLIT,$0-0
+	JMP	libc_sysctl(SB)
diff --git a/src/syscall/zsyscall_darwin_arm.go b/src/syscall/zsyscall_darwin_arm.go
index 2a643f209f..73ee205d33 100644
--- a/src/syscall/zsyscall_darwin_arm.go
+++ b/src/syscall/zsyscall_darwin_arm.go
@@ -1870,27 +1870,6 @@ func libc_exit_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) {
-	var _p0 unsafe.Pointer
-	if len(mib) > 0 {
-		_p0 = unsafe.Pointer(&mib[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-func libc_sysctl_trampoline()
-
-//go:linkname libc_sysctl libc_sysctl
-//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 	r0, _, e1 := syscall(funcPC(libc_fcntl_trampoline), uintptr(fd), uintptr(cmd), uintptr(arg))
 	val = int(r0)
diff --git a/src/syscall/zsyscall_darwin_arm.s b/src/syscall/zsyscall_darwin_arm.s
index c7cd83d83e..6462a198b0 100644
--- a/src/syscall/zsyscall_darwin_arm.s
+++ b/src/syscall/zsyscall_darwin_arm.s
@@ -229,8 +229,6 @@ TEXT ·libc_execve_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_execve(SB)
 TEXT ·libc_exit_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_exit(SB)
-TEXT ·libc_sysctl_trampoline(SB),NOSPLIT,$0-0
-	JMP	libc_sysctl(SB)
 TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unlinkat(SB)
 TEXT ·libc_openat_trampoline(SB),NOSPLIT,$0-0
diff --git a/src/syscall/zsyscall_darwin_arm64.go b/src/syscall/zsyscall_darwin_arm64.go
index 0b77839869..bbe092cd07 100644
--- a/src/syscall/zsyscall_darwin_arm64.go
+++ b/src/syscall/zsyscall_darwin_arm64.go
@@ -1870,27 +1870,6 @@ func libc_exit_trampoline()
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func sysctl(mib []_C_int, old *byte, oldlen *uintptr, new *byte, newlen uintptr) (err error) {
-	var _p0 unsafe.Pointer
-	if len(mib) > 0 {
-		_p0 = unsafe.Pointer(&mib[0])
-	} else {
-		_p0 = unsafe.Pointer(&_zero)
-	}
-	_, _, e1 := syscall6(funcPC(libc_sysctl_trampoline), uintptr(_p0), uintptr(len(mib)), uintptr(unsafe.Pointer(old)), uintptr(unsafe.Pointer(oldlen)), uintptr(unsafe.Pointer(new)), uintptr(newlen))
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-func libc_sysctl_trampoline()
-
-//go:linkname libc_sysctl libc_sysctl
-//go:cgo_import_dynamic libc_sysctl sysctl "/usr/lib/libSystem.B.dylib"
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (val int, err error) {
 	r0, _, e1 := syscall(funcPC(libc_fcntl_trampoline), uintptr(fd), uintptr(cmd), uintptr(arg))
 	val = int(r0)
diff --git a/src/syscall/zsyscall_darwin_arm64.s b/src/syscall/zsyscall_darwin_arm64.s
index 7b8b3764a8..ec2210f1df 100644
--- a/src/syscall/zsyscall_darwin_arm64.s
+++ b/src/syscall/zsyscall_darwin_arm64.s
@@ -229,8 +229,6 @@ TEXT ·libc_execve_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_execve(SB)
 TEXT ·libc_exit_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_exit(SB)
-TEXT ·libc_sysctl_trampoline(SB),NOSPLIT,$0-0
-	JMP	libc_sysctl(SB)
 TEXT ·libc_unlinkat_trampoline(SB),NOSPLIT,$0-0
 	JMP	libc_unlinkat(SB)
 TEXT ·libc_openat_trampoline(SB),NOSPLIT,$0-0
diff --git a/test/fixedbugs/issue31747.go b/test/fixedbugs/issue31747.go
index dfb585c613..420fe30735 100644
--- a/test/fixedbugs/issue31747.go
+++ b/test/fixedbugs/issue31747.go
@@ -8,11 +8,11 @@ package p
 
 // numeric literals
 const (
-	_ = 1_000 // ERROR "underscores in numeric literals only supported as of -lang=go1.13"
-	_ = 0b111 // ERROR "binary literals only supported as of -lang=go1.13"
-	_ = 0o567 // ERROR "0o/0O-style octal literals only supported as of -lang=go1.13"
+	_ = 1_000 // ERROR "underscores in numeric literals requires go1.13 or later \(-lang was set to go1.12; check go.mod\)"
+	_ = 0b111 // ERROR "binary literals requires go1.13 or later"
+	_ = 0o567 // ERROR "0o/0O-style octal literals requires go1.13 or later"
 	_ = 0xabc // ok
-	_ = 0x0p1 // ERROR "hexadecimal floating-point literals only supported as of -lang=go1.13"
+	_ = 0x0p1 // ERROR "hexadecimal floating-point literals requires go1.13 or later"
 
 	_ = 0B111 // ERROR "binary"
 	_ = 0O567 // ERROR "octal"
@@ -29,6 +29,6 @@ const (
 // signed shift counts
 var (
 	s int
-	_ = 1 << s // ERROR "signed shift count type int, only supported as of -lang=go1.13"
+	_ = 1 << s // ERROR "invalid operation: 1 << s \(signed shift count type int\) requires go1.13 or later"
 	_ = 1 >> s // ERROR "signed shift count"
 )