	Vim Go	Visual Studio Code Go	vim	Visual Studio Code	Gogland	Atom
Editing features	Editing features
Build and run from the editor/IDE	Yes	Yes	Yes	Yes
Autocompletion of identifers (variable, method, and function names)	Yes	Yes	Yes	Yes
Autocompletion based on type	Type-aware autocompletion	No	No	Yes	No
Rename identifiers	Yes	Yes	Yes	Yes	Auto format, build, vet, and lint on save	Yes	Yes	Yes¹	Yes
Auto insert import paths and remove unused on save	Yes	Yes	Yes²	Yes
Auto generate JSON, XML tags for struct fields	Yes	Yes	Yes	Yes
Navigation features	Navigation features
Display documentation inline, or open godoc in browser	Yes	Yes	Yes	Yes	Switch between `.go` and `_test.go` file	Yes	Yes	Yes	No
Jump to definition and referees	Yes	Yes	Yes	Yes
Look up for interface implementations	Yes	Yes	Yes	Yes	Search for callers and callees	Yes	Yes	Yes	Yes
Testing and debugging features	Testing and debugging features
Debugger support	No	Yes	Yes	Yes³
Run a single test case, all tests from file, or all tests from a package	Yes	Yes	Yes	No
Auto generate tests for packages, files and identifiers	No	Yes	No	No
Debug tests	No	Yes	Yes	Yes³
Display test coverage	Yes	Yes	Yes	Yes		Install	Install	Install	Install
+{{if not $.GoogleCN}} +{{end}}
Try Go
// You can edit this code!
@@ -26,10 +28,10 @@ </pre>
 </div>
 <div class="buttons">
 <a class="run" href="#" title="Run this code [shift-enter]">Run</a>
-{{if $.Share}}
+{{if not $.GoogleCN}}
 <a class="share" href="#" title="Share this code">Share</a>
-{{end}}
 <a class="tour" href="//tour.golang.org/" title="Learn Go from your browser">Tour</a>
+{{end}}
 </div>
 <div class="toys">
 <select>
@@ -68,85 +70,91 @@ </div>
 
 <div style="clear: both"></div>
 
+{{if not $.GoogleCN}}
 <div class="left">
-
-<div id="video">
-<div class="rootHeading">Featured video</div>
-<iframe width="415" height="241" src="//www.youtube.com/embed/ytEkHepK08c" frameborder="0" allowfullscreen></iframe>
-</div>
-
+  <div id="video">
+    <div class="rootHeading">Featured video</div>
+    <iframe width="415" height="241" src="//www.youtube.com/embed/ytEkHepK08c" frameborder="0" allowfullscreen></iframe>
+  </div>
 </div>
 
 <div class="right">
-
-<div id="blog">
-<div class="rootHeading">Featured articles</div>
-<div class="read"><a href="//blog.golang.org/">Read more</a></div>
-</div>
-
+	<div id="blog">
+		<div class="rootHeading">Featured articles</div>
+		<div class="read"><a href="//blog.golang.org/">Read more</a></div>
+	</div>
 </div>
+{{end}}
 
 <div style="clear: both;"></div>
 
-<script type="text/javascript">
+<script>
+(function() {
+	'use strict';
 
-function readableTime(t) {
-	var m = ["January", "February", "March", "April", "May", "June", "July",
-		"August", "September", "October", "November", "December"];
-	var p = t.substring(0, t.indexOf("T")).split("-");
-	var d = new Date(p[0], p[1]-1, p[2]);
-	return d.getDate() + " " + m[d.getMonth()] + " " + d.getFullYear();
-}
+	window.initFuncs.push(function() {
+		// Set up playground if enabled.
+		if (window.playground) {
+			window.playground({
+				"codeEl":        "#learn .code",
+				"outputEl":      "#learn .output",
+				"runEl":         "#learn .run",
+				"shareEl":       "#learn .share",
+				"shareRedirect": "//play.golang.org/p/",
+				"toysEl":        "#learn .toys select"
+			});
+		} else {
+			$('#learn').hide()
+		}
+	});
 
-function feedLoaded(result) {
-	var blog = document.getElementById("blog");
-	var read = blog.getElementsByClassName("read")[0];
-	for (var i = 0; i < result.length && i < 2; i++) {
-		var entry = result[i];
-		var title = document.createElement("a");
-		title.className = "title";
-		title.href = entry.Link;
-		title.innerHTML = entry.Title;
-		blog.insertBefore(title, read);
-		var extract = document.createElement("div");
-		extract.className = "extract";
-		extract.innerHTML = entry.Summary;
-		blog.insertBefore(extract, read);
-		var when = document.createElement("div");
-		when.className = "when";
-		when.innerHTML = "Published " + readableTime(entry.Time);
-		blog.insertBefore(when, read);
+	{{if not $.GoogleCN}}
+
+	function readableTime(t) {
+		var m = ["January", "February", "March", "April", "May", "June", "July",
+			"August", "September", "October", "November", "December"];
+		var p = t.substring(0, t.indexOf("T")).split("-");
+		var d = new Date(p[0], p[1]-1, p[2]);
+		return d.getDate() + " " + m[d.getMonth()] + " " + d.getFullYear();
 	}
-}
 
-window.initFuncs.push(function() {
-	// Set up playground if enabled.
-	if (window.playground) {
-		window.playground({
-			"codeEl":        "#learn .code",
-			"outputEl":      "#learn .output",
-			"runEl":         "#learn .run",
-			"shareEl":       "#learn .share",
-			"shareRedirect": "//play.golang.org/p/",
-			"toysEl":        "#learn .toys select"
-		});
-	} else {
-		$('#learn').hide()
+	window.feedLoaded = function(result) {
+		var blog = document.getElementById("blog");
+		var read = blog.getElementsByClassName("read")[0];
+		for (var i = 0; i < result.length && i < 2; i++) {
+			var entry = result[i];
+			var title = document.createElement("a");
+			title.className = "title";
+			title.href = entry.Link;
+			title.innerHTML = entry.Title;
+			blog.insertBefore(title, read);
+			var extract = document.createElement("div");
+			extract.className = "extract";
+			extract.innerHTML = entry.Summary;
+			blog.insertBefore(extract, read);
+			var when = document.createElement("div");
+			when.className = "when";
+			when.innerHTML = "Published " + readableTime(entry.Time);
+			blog.insertBefore(when, read);
+		}
 	}
 
-	// Load blog feed.
-	$('<script/>').attr('text', 'text/javascript')
-		.attr('src', '//blog.golang.org/.json?jsonp=feedLoaded')
-		.appendTo('body');
+	window.initFuncs.push(function() {
+		// Load blog feed.
+		$('<script/>').attr('text', 'text/javascript')
+			.attr('src', '//blog.golang.org/.json?jsonp=feedLoaded')
+			.appendTo('body');
 
-	// Set the video at random.
-	var videos = [
-		{h: 241, s: "//www.youtube.com/embed/ytEkHepK08c"}, // Tour of Go
-		{h: 241, s: "//www.youtube.com/embed/f6kdp27TYZs"}, // Concurrency Patterns
-		{h: 233, s: "//player.vimeo.com/video/69237265"}    // Simple environment
-	];
-	var v = videos[Math.floor(Math.random()*videos.length)];
-	$('#video iframe').attr('height', v.h).attr('src', v.s);
-});
+		// Set the video at random.
+		var videos = [
+			{h: 241, s: "//www.youtube.com/embed/ytEkHepK08c"}, // Tour of Go
+			{h: 241, s: "//www.youtube.com/embed/f6kdp27TYZs"}, // Concurrency Patterns
+			{h: 233, s: "//player.vimeo.com/video/69237265"}    // Simple environment
+		];
+		var v = videos[Math.floor(Math.random()*videos.length)];
+		$('#video iframe').attr('height', v.h).attr('src', v.s);
+	});
 
+	{{end}}
+})();
 </script>
diff --git a/misc/cgo/errors/ptr.go b/misc/cgo/errors/ptr.go
index 4dafbdf3c011766b99a53e1e118dfce2e3f76cab..3e117666bffb5ba35d833325401b1e8e81a6ade5 100644
--- a/misc/cgo/errors/ptr.go
+++ b/misc/cgo/errors/ptr.go
@@ -343,6 +343,14 @@ 		imports: []string{"unsafe"},
 		body:    `var b C.char; p := &b; C.f((*C.u)(unsafe.Pointer(&p)))`,
 		fail:    false,
 	},
+	{
+		// Issue #21306.
+		name:    "preempt-during-call",
+		c:       `void f() {}`,
+		imports: []string{"runtime", "sync"},
+		body:    `var wg sync.WaitGroup; wg.Add(100); for i := 0; i < 100; i++ { go func(i int) { for j := 0; j < 100; j++ { C.f(); runtime.GOMAXPROCS(i) }; wg.Done() }(i) }; wg.Wait()`,
+		fail:    false,
+	},
 }
 
 func main() {
diff --git a/misc/cgo/testsanitizers/test.bash b/misc/cgo/testsanitizers/test.bash
index ea08f374325cbba9c13163d9685e68f2f4eda5ad..9f80af6c507557be2eefecb0edb28a343311b2bb 100755
--- a/misc/cgo/testsanitizers/test.bash
+++ b/misc/cgo/testsanitizers/test.bash
@@ -156,15 +156,18 @@     ok=yes
     if ! $CC -fsanitize=thread ${TMPDIR}/testsanitizers$$.c -o ${TMPDIR}/testsanitizers$$ &> ${TMPDIR}/testsanitizers$$.err; then
 	ok=no
     fi
-     if grep "unrecognized" ${TMPDIR}/testsanitizers$$.err >& /dev/null; then
+    if grep "unrecognized" ${TMPDIR}/testsanitizers$$.err >& /dev/null; then
 	echo "skipping tsan tests: -fsanitize=thread not supported"
 	tsan=no
-     elif test "$ok" != "yes"; then
-	 cat ${TMPDIR}/testsanitizers$$.err
-	 echo "skipping tsan tests: -fsanitizer=thread build failed"
-	 tsan=no
-     fi
-     rm -f ${TMPDIR}/testsanitizers$$*
+    elif test "$ok" != "yes"; then
+	cat ${TMPDIR}/testsanitizers$$.err
+	echo "skipping tsan tests: -fsanitizer=thread build failed"
+	tsan=no
+    elif ! ${TMPDIR}/testsanitizers$$ 2>&1; then
+	echo "skipping tsan tests: running tsan program failed"
+	tsan=no
+    fi
+    rm -f ${TMPDIR}/testsanitizers$$*
 fi
 
 # Run a TSAN test.
@@ -196,8 +199,10 @@
     # These tests are only reliable using clang or GCC version 7 or later.
     # Otherwise runtime/cgo/libcgo.h can't tell whether TSAN is in use.
     ok=false
+    clang=false
     if ${CC} --version | grep clang >/dev/null 2>&1; then
 	ok=true
+	clang=true
     else
 	ver=$($CC -dumpversion)
 	major=$(echo $ver | sed -e 's/\([0-9]*\).*/\1/')
@@ -213,9 +218,13 @@ 	# These tests require rebuilding os/user with -fsanitize=thread.
 	testtsan tsan5.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
 	testtsan tsan6.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
 	testtsan tsan7.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
-	testtsan tsan10.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
-	testtsan tsan11.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
-	testtsan tsan12.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
+
+	# The remaining tests reportedly hang when built with GCC; issue #21196.
+	if test "$clang" = "true"; then
+	    testtsan tsan10.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
+	    testtsan tsan11.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
+	    testtsan tsan12.go "CGO_CFLAGS=-fsanitize=thread CGO_LDFLAGS=-fsanitize=thread" "-installsuffix=tsan"
+	fi
 
 	testtsanshared
     fi
diff --git a/src/cmd/compile/internal/arm/ssa.go b/src/cmd/compile/internal/arm/ssa.go
index 343f2d3aec7daa1784288f446ed13e2fc7a0d7fd..93abee3da0f09b2aadb4a88bd42a8482f92864dc 100644
--- a/src/cmd/compile/internal/arm/ssa.go
+++ b/src/cmd/compile/internal/arm/ssa.go
@@ -464,6 +464,7 @@ 		genregshift(s, v.Op.Asm(), v.Args[0].Reg(), v.Args[1].Reg(), v.Args[2].Reg(), 0, arm.SHIFT_AR)
 	case ssa.OpARMMOVWaddr:
 		p := s.Prog(arm.AMOVW)
 		p.From.Type = obj.TYPE_ADDR
+		p.From.Reg = v.Args[0].Reg()
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = v.Reg()
 
@@ -485,7 +486,6 @@ 			gc.AddAux(&p.From, v)
 		case nil:
 			// No sym, just MOVW $off(SP), R
 			wantreg = "SP"
-			p.From.Reg = arm.REGSP
 			p.From.Offset = v.AuxInt
 		}
 		if reg := v.Args[0].RegName(); reg != wantreg {
diff --git a/src/cmd/compile/internal/arm64/ssa.go b/src/cmd/compile/internal/arm64/ssa.go
index dec6a4e93ede54eaa22a4048f80fa55b53abdb4b..0f9e82c727db3b15d88cae8477908f821e9f4457 100644
--- a/src/cmd/compile/internal/arm64/ssa.go
+++ b/src/cmd/compile/internal/arm64/ssa.go
@@ -260,6 +260,7 @@ 		genshift(s, v.Op.Asm(), v.Args[0].Reg(), v.Args[1].Reg(), 0, arm64.SHIFT_AR, v.AuxInt)
 	case ssa.OpARM64MOVDaddr:
 		p := s.Prog(arm64.AMOVD)
 		p.From.Type = obj.TYPE_ADDR
+		p.From.Reg = v.Args[0].Reg()
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = v.Reg()
 
@@ -281,7 +282,6 @@ 			gc.AddAux(&p.From, v)
 		case nil:
 			// No sym, just MOVD $off(SP), R
 			wantreg = "SP"
-			p.From.Reg = arm64.REGSP
 			p.From.Offset = v.AuxInt
 		}
 		if reg := v.Args[0].RegName(); reg != wantreg {
diff --git a/src/cmd/compile/internal/gc/asm_test.go b/src/cmd/compile/internal/gc/asm_test.go
index 221b8497f15984d834118d81045eb2a3bd1d73dd..08ec638f44ef7105d2dad1db5631c17fff5a2f79 100644
--- a/src/cmd/compile/internal/gc/asm_test.go
+++ b/src/cmd/compile/internal/gc/asm_test.go
@@ -898,6 +898,17 @@ 		    return *((*[4]byte)(a)) != *((*[4]byte)(b))
 		}`,
 		[]string{"\tCMPL\t[A-Z]"},
 	},
+	{
+		// make sure assembly output has matching offset and base register.
+		`
+		func f72(a, b int) int {
+			var x [16]byte // use some frame
+			_ = x
+			return b
+		}
+		`,
+		[]string{"b\\+40\\(SP\\)"},
+	},
 }
 
 var linux386Tests = []*asmTest{
@@ -1302,6 +1313,17 @@ 		}
 		`,
 		[]string{"\tCLZ\t"},
 	},
+	{
+		// make sure assembly output has matching offset and base register.
+		`
+		func f13(a, b int) int {
+			var x [16]byte // use some frame
+			_ = x
+			return b
+		}
+		`,
+		[]string{"b\\+4\\(FP\\)"},
+	},
 }
 
 var linuxARM64Tests = []*asmTest{
@@ -1473,7 +1495,7 @@ 			b = a
 			return
 		}
 		`,
-		[]string{"\tMOVD\t\"\"\\.a\\+[0-9]+\\(RSP\\), R[0-9]+", "\tMOVD\tR[0-9]+, \"\"\\.b\\+[0-9]+\\(RSP\\)"},
+		[]string{"\tMOVD\t\"\"\\.a\\+[0-9]+\\(FP\\), R[0-9]+", "\tMOVD\tR[0-9]+, \"\"\\.b\\+[0-9]+\\(FP\\)"},
 	},
 }
 
diff --git a/src/cmd/compile/internal/mips/ssa.go b/src/cmd/compile/internal/mips/ssa.go
index d2b4885eaad9c5bec0d8730852ec93a1ceeaadf3..e65515a85b0102876c4b6dd72952d34f8d02f43b 100644
--- a/src/cmd/compile/internal/mips/ssa.go
+++ b/src/cmd/compile/internal/mips/ssa.go
@@ -273,6 +273,7 @@ 		p.Reg = v.Args[1].Reg()
 	case ssa.OpMIPSMOVWaddr:
 		p := s.Prog(mips.AMOVW)
 		p.From.Type = obj.TYPE_ADDR
+		p.From.Reg = v.Args[0].Reg()
 		var wantreg string
 		// MOVW $sym+off(base), R
 		// the assembler expands it as the following:
@@ -291,7 +292,6 @@ 			gc.AddAux(&p.From, v)
 		case nil:
 			// No sym, just MOVW $off(SP), R
 			wantreg = "SP"
-			p.From.Reg = mips.REGSP
 			p.From.Offset = v.AuxInt
 		}
 		if reg := v.Args[0].RegName(); reg != wantreg {
diff --git a/src/cmd/compile/internal/mips64/ssa.go b/src/cmd/compile/internal/mips64/ssa.go
index 5a7a6019422b112b514018f579baacbbc8179cdb..db163f3e9d0776650062df3f4887b89fca2722b6 100644
--- a/src/cmd/compile/internal/mips64/ssa.go
+++ b/src/cmd/compile/internal/mips64/ssa.go
@@ -247,6 +247,7 @@ 		p.Reg = v.Args[1].Reg()
 	case ssa.OpMIPS64MOVVaddr:
 		p := s.Prog(mips.AMOVV)
 		p.From.Type = obj.TYPE_ADDR
+		p.From.Reg = v.Args[0].Reg()
 		var wantreg string
 		// MOVV $sym+off(base), R
 		// the assembler expands it as the following:
@@ -265,7 +266,6 @@ 			gc.AddAux(&p.From, v)
 		case nil:
 			// No sym, just MOVV $off(SP), R
 			wantreg = "SP"
-			p.From.Reg = mips.REGSP
 			p.From.Offset = v.AuxInt
 		}
 		if reg := v.Args[0].RegName(); reg != wantreg {
diff --git a/src/cmd/compile/internal/ppc64/ssa.go b/src/cmd/compile/internal/ppc64/ssa.go
index a95dabccf0be1215e2dab583930287d76a18ede4..5fe140fdcf16e47041f250375cfe0512d307f066 100644
--- a/src/cmd/compile/internal/ppc64/ssa.go
+++ b/src/cmd/compile/internal/ppc64/ssa.go
@@ -638,6 +638,7 @@
 	case ssa.OpPPC64MOVDaddr:
 		p := s.Prog(ppc64.AMOVD)
 		p.From.Type = obj.TYPE_ADDR
+		p.From.Reg = v.Args[0].Reg()
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = v.Reg()
 
@@ -660,7 +661,6 @@ 			gc.AddAux(&p.From, v)
 		case nil:
 			// No sym, just MOVD $off(SP), R
 			wantreg = "SP"
-			p.From.Reg = ppc64.REGSP
 			p.From.Offset = v.AuxInt
 		}
 		if reg := v.Args[0].RegName(); reg != wantreg {
diff --git a/src/cmd/go/go_test.go b/src/cmd/go/go_test.go
index e706e27bdf366305c814f755c31b579fd47e1b50..7d80d965ae6dc1ffd41a590a537f6fb4b177d75b 100644
--- a/src/cmd/go/go_test.go
+++ b/src/cmd/go/go_test.go
@@ -4314,3 +4314,20 @@ 	if have != want {
 		t.Errorf("reduced output:<<<\n%s>>> want:<<<\n%s>>>", have, want)
 	}
 }
+
+func TestListTests(t *testing.T) {
+	var tg *testgoData
+	testWith := func(listName, expected string) func(*testing.T) {
+		return func(t *testing.T) {
+			tg = testgo(t)
+			defer tg.cleanup()
+			tg.run("test", "./testdata/src/testlist/...", fmt.Sprintf("-list=%s", listName))
+			tg.grepStdout(expected, fmt.Sprintf("-test.list=%s returned %q, expected %s", listName, tg.getStdout(), expected))
+		}
+	}
+
+	t.Run("Test", testWith("Test", "TestSimple"))
+	t.Run("Bench", testWith("Benchmark", "BenchmarkSimple"))
+	t.Run("Example1", testWith("Example", "ExampleSimple"))
+	t.Run("Example2", testWith("Example", "ExampleWithEmptyOutput"))
+}
diff --git a/src/cmd/go/testdata/src/testlist/bench_test.go b/src/cmd/go/testdata/src/testlist/bench_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..22f147b63390de175d1b98af310b08b6f0bb7307
--- /dev/null
+++ b/src/cmd/go/testdata/src/testlist/bench_test.go
@@ -0,0 +1,14 @@
+package testlist
+
+import (
+	"fmt"
+	"testing"
+)
+
+func BenchmarkSimplefunc(b *testing.B) {
+	b.StopTimer()
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		_ = fmt.Sprint("Test for bench")
+	}
+}
diff --git a/src/cmd/go/testdata/src/testlist/example_test.go b/src/cmd/go/testdata/src/testlist/example_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..0298dfde81e2a3926cb644187c39a2dcd72147fd
--- /dev/null
+++ b/src/cmd/go/testdata/src/testlist/example_test.go
@@ -0,0 +1,21 @@
+package testlist
+
+import (
+	"fmt"
+)
+
+func ExampleSimple() {
+	fmt.Println("Test with Output.")
+
+	// Output: Test with Output.
+}
+
+func ExampleWithEmptyOutput() {
+	fmt.Println("")
+
+	// Output:
+}
+
+func ExampleNoOutput() {
+	_ = fmt.Sprint("Test with no output")
+}
diff --git a/src/cmd/go/testdata/src/testlist/test_test.go b/src/cmd/go/testdata/src/testlist/test_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..bdc09f27c5b10338d3da75a25dfb16bd03cf918f
--- /dev/null
+++ b/src/cmd/go/testdata/src/testlist/test_test.go
@@ -0,0 +1,10 @@
+package testlist
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestSimple(t *testing.T) {
+	_ = fmt.Sprint("Test simple")
+}
diff --git a/src/cmd/internal/obj/arm/asm5.go b/src/cmd/internal/obj/arm/asm5.go
index cfda99f60289b33921823e4ec5d9043d48acd8bc..8abf732b2caf70df140040d12b47b86932530966 100644
--- a/src/cmd/internal/obj/arm/asm5.go
+++ b/src/cmd/internal/obj/arm/asm5.go
@@ -1167,6 +1167,11 @@
 			return C_ADDR
 
 		case obj.NAME_AUTO:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-SP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = c.autosize + a.Offset
 			if t := immaddr(int32(c.instoffset)); t != 0 {
 				if immhalf(int32(c.instoffset)) {
@@ -1185,6 +1190,11 @@
 			return C_LAUTO
 
 		case obj.NAME_PARAM:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-FP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = c.autosize + a.Offset + 4
 			if t := immaddr(int32(c.instoffset)); t != 0 {
 				if immhalf(int32(c.instoffset)) {
@@ -1285,10 +1295,20 @@ 			c.instoffset = 0 // s.b. unused but just in case
 			return C_LCONADDR
 
 		case obj.NAME_AUTO:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-SP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = c.autosize + a.Offset
 			return c.aconsize()
 
 		case obj.NAME_PARAM:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-FP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = c.autosize + a.Offset + 4
 			return c.aconsize()
 		}
diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
index 04a481863ad6f96600a7dcd93503fe17241e7924..4419909f69149e4c2c2f51644eefda4cd1663deb 100644
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@@ -1149,10 +1149,20 @@ 		case obj.NAME_GOTREF:
 			return C_GOTADDR
 
 		case obj.NAME_AUTO:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-SP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset
 			return autoclass(c.instoffset)
 
 		case obj.NAME_PARAM:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-FP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset + 8
 			return autoclass(c.instoffset)
 
@@ -1228,10 +1238,20 @@ 			c.instoffset = a.Offset
 			return C_VCONADDR
 
 		case obj.NAME_AUTO:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-SP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset
 			goto aconsize
 
 		case obj.NAME_PARAM:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-FP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset + 8
 			goto aconsize
 		}
diff --git a/src/cmd/internal/obj/mips/asm0.go b/src/cmd/internal/obj/mips/asm0.go
index 3cfb260d60398700e1377d45e3a40c86c1dfefd6..6257e5b83d2a084022c7c92f1f11e99348dd16b8 100644
--- a/src/cmd/internal/obj/mips/asm0.go
+++ b/src/cmd/internal/obj/mips/asm0.go
@@ -556,6 +556,11 @@ 			}
 			return C_LEXT
 
 		case obj.NAME_AUTO:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-SP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SAUTO
@@ -563,6 +568,11 @@ 			}
 			return C_LAUTO
 
 		case obj.NAME_PARAM:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-FP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset + c.ctxt.FixedFrameSize()
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SAUTO
@@ -616,6 +626,11 @@ 			}
 			return C_LECON
 
 		case obj.NAME_AUTO:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-SP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SACON
@@ -623,6 +638,11 @@ 			}
 			return C_LACON
 
 		case obj.NAME_PARAM:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-FP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset + c.ctxt.FixedFrameSize()
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SACON
diff --git a/src/cmd/internal/obj/ppc64/asm9.go b/src/cmd/internal/obj/ppc64/asm9.go
index bdbac03f9c043324547bdf0ba9e369dea4a6f4b8..4d787b1c352eea3734210003ad54d8ece2efd7ed 100644
--- a/src/cmd/internal/obj/ppc64/asm9.go
+++ b/src/cmd/internal/obj/ppc64/asm9.go
@@ -758,6 +758,11 @@ 		case obj.NAME_GOTREF:
 			return C_GOTADDR
 
 		case obj.NAME_AUTO:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-SP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SAUTO
@@ -765,6 +770,11 @@ 			}
 			return C_LAUTO
 
 		case obj.NAME_PARAM:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-FP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset + c.ctxt.FixedFrameSize()
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SAUTO
@@ -817,6 +827,11 @@ 			/* not sure why this barfs */
 			return C_LCON
 
 		case obj.NAME_AUTO:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-SP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SACON
@@ -824,6 +839,11 @@ 			}
 			return C_LACON
 
 		case obj.NAME_PARAM:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-FP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset + c.ctxt.FixedFrameSize()
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SACON
diff --git a/src/cmd/internal/obj/s390x/asmz.go b/src/cmd/internal/obj/s390x/asmz.go
index 3bba7b2a5ce905f4d4c6b34e1c95c7a3bce2bc24..6d2b870f0aca95a5cf8e4714a787bb752edd3036 100644
--- a/src/cmd/internal/obj/s390x/asmz.go
+++ b/src/cmd/internal/obj/s390x/asmz.go
@@ -505,6 +505,11 @@ 		case obj.NAME_GOTREF:
 			return C_GOTADDR
 
 		case obj.NAME_AUTO:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-SP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SAUTO
@@ -512,6 +517,11 @@ 			}
 			return C_LAUTO
 
 		case obj.NAME_PARAM:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-FP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset + c.ctxt.FixedFrameSize()
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SAUTO
@@ -567,6 +577,11 @@
 			return C_SYMADDR
 
 		case obj.NAME_AUTO:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-SP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SACON
@@ -574,6 +589,11 @@ 			}
 			return C_LACON
 
 		case obj.NAME_PARAM:
+			if a.Reg == REGSP {
+				// unset base register for better printing, since
+				// a.Offset is still relative to pseudo-FP.
+				a.Reg = obj.REG_NONE
+			}
 			c.instoffset = int64(c.autosize) + a.Offset + c.ctxt.FixedFrameSize()
 			if c.instoffset >= -BIG && c.instoffset < BIG {
 				return C_SACON
diff --git a/src/cmd/vet/main.go b/src/cmd/vet/main.go
index 77376c90ed16bb0fbb7e4107c5cf07693a775536..34c5297b89f9e7faeef89a4291819b31d7c47fd5 100644
--- a/src/cmd/vet/main.go
+++ b/src/cmd/vet/main.go
@@ -349,8 +349,9 @@ 	pkg.path = astFiles[0].Name.Name
 	pkg.files = files
 	// Type check the package.
 	err := pkg.check(fs, astFiles)
-	if err != nil && *verbose {
-		warnf("%s", err)
+	if err != nil {
+		// Note that we only report this error when *verbose.
+		Println(err)
 	}
 
 	// Check.
diff --git a/src/cmd/vet/testdata/cgo/cgo3.go b/src/cmd/vet/testdata/cgo/cgo3.go
new file mode 100644
index 0000000000000000000000000000000000000000..0b1518e1f930a572b5497da80346805b6ceab7f3
--- /dev/null
+++ b/src/cmd/vet/testdata/cgo/cgo3.go
@@ -0,0 +1,13 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Used by TestVetVerbose to test that vet -v doesn't fail because it
+// can't find "C".
+
+package testdata
+
+import "C"
+
+func F() {
+}
diff --git a/src/cmd/vet/vet_test.go b/src/cmd/vet/vet_test.go
index b3d5c663a714c755503a254f74f41a2dc5aff312..8db8ff4d20266f2a325920551275d1aa09689c5c 100644
--- a/src/cmd/vet/vet_test.go
+++ b/src/cmd/vet/vet_test.go
@@ -205,3 +205,15 @@ 			}
 		})
 	}
 }
+
+// Issue #21188.
+func TestVetVerbose(t *testing.T) {
+	t.Parallel()
+	Build(t)
+	cmd := exec.Command("./"+binary, "-v", "-all", "testdata/cgo/cgo3.go")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Logf("%s", out)
+		t.Error(err)
+	}
+}
diff --git a/src/encoding/binary/example_test.go b/src/encoding/binary/example_test.go
index 2b52a47d129cf7a0968680874ad714251a4238b5..a8b8dba6507706da837ddb1b68761d1abf21e308 100644
--- a/src/encoding/binary/example_test.go
+++ b/src/encoding/binary/example_test.go
@@ -68,3 +68,94 @@ 	fmt.Printf("%#04x %#04x\n", x1, x2)
 	// Output:
 	// 0x03e8 0x07d0
 }
+
+func ExamplePutUvarint() {
+	buf := make([]byte, binary.MaxVarintLen64)
+
+	for _, x := range []uint64{1, 2, 127, 128, 255, 256} {
+		n := binary.PutUvarint(buf, x)
+		fmt.Printf("%x\n", buf[:n])
+	}
+	// Output:
+	// 01
+	// 02
+	// 7f
+	// 8001
+	// ff01
+	// 8002
+}
+
+func ExamplePutVarint() {
+	buf := make([]byte, binary.MaxVarintLen64)
+
+	for _, x := range []int64{-65, -64, -2, -1, 0, 1, 2, 63, 64} {
+		n := binary.PutVarint(buf, x)
+		fmt.Printf("%x\n", buf[:n])
+	}
+	// Output:
+	// 8101
+	// 7f
+	// 03
+	// 01
+	// 00
+	// 02
+	// 04
+	// 7e
+	// 8001
+}
+
+func ExampleUvarint() {
+	inputs := [][]byte{
+		[]byte{0x01},
+		[]byte{0x02},
+		[]byte{0x7f},
+		[]byte{0x80, 0x01},
+		[]byte{0xff, 0x01},
+		[]byte{0x80, 0x02},
+	}
+	for _, b := range inputs {
+		x, n := binary.Uvarint(b)
+		if n != len(b) {
+			fmt.Println("Uvarint did not consume all of in")
+		}
+		fmt.Println(x)
+	}
+	// Output:
+	// 1
+	// 2
+	// 127
+	// 128
+	// 255
+	// 256
+}
+
+func ExampleVarint() {
+	inputs := [][]byte{
+		[]byte{0x81, 0x01},
+		[]byte{0x7f},
+		[]byte{0x03},
+		[]byte{0x01},
+		[]byte{0x00},
+		[]byte{0x02},
+		[]byte{0x04},
+		[]byte{0x7e},
+		[]byte{0x80, 0x01},
+	}
+	for _, b := range inputs {
+		x, n := binary.Varint(b)
+		if n != len(b) {
+			fmt.Println("Varint did not consume all of in")
+		}
+		fmt.Println(x)
+	}
+	// Output:
+	// -65
+	// -64
+	// -2
+	// -1
+	// 0
+	// 1
+	// 2
+	// 63
+	// 64
+}
diff --git a/src/go/ast/ast.go b/src/go/ast/ast.go
index 77ef98ceaf9d2f8e8c8b59d35fe3286e7e6c40ae..9ab7b1e62568fe75754f002e605569e36944ea16 100644
--- a/src/go/ast/ast.go
+++ b/src/go/ast/ast.go
@@ -969,14 +969,14 @@ // via Doc and Comment fields.
 //
 // For correct printing of source code containing comments (using packages
 // go/format and go/printer), special care must be taken to update comments
-// when a File's syntax tree is modified: For printing, comments are inter-
-// spersed between tokens based on their position. If syntax tree nodes are
+// when a File's syntax tree is modified: For printing, comments are interspersed
+// between tokens based on their position. If syntax tree nodes are
 // removed or moved, relevant comments in their vicinity must also be removed
 // (from the File.Comments list) or moved accordingly (by updating their
 // positions). A CommentMap may be used to facilitate some of these operations.
 //
-// Whether and how a comment is associated with a node depends on the inter-
-// pretation of the syntax tree by the manipulating program: Except for Doc
+// Whether and how a comment is associated with a node depends on the
+// interpretation of the syntax tree by the manipulating program: Except for Doc
 // and Comment comments directly associated with nodes, the remaining comments
 // are "free-floating" (see also issues #18593, #20744).
 //
diff --git a/src/go/parser/parser.go b/src/go/parser/parser.go
index 1b4309b5da739a870056299056123719d8efdeee..2b58724521fb41cec65f9f3d8e88da50ab80e74d 100644
--- a/src/go/parser/parser.go
+++ b/src/go/parser/parser.go
@@ -1707,8 +1707,8 @@ 			return stmt, false
 		}
 		// The label declaration typically starts at x[0].Pos(), but the label
 		// declaration may be erroneous due to a token after that position (and
-		// before the ':'). If SpuriousErrors is not set, the (only) error re-
-		// ported for the line is the illegal label error instead of the token
+		// before the ':'). If SpuriousErrors is not set, the (only) error
+		// reported for the line is the illegal label error instead of the token
 		// before the ':' that caused the problem. Thus, use the (latest) colon
 		// position for error reporting.
 		p.error(colon, "illegal label declaration")
diff --git a/src/internal/poll/fd_windows.go b/src/internal/poll/fd_windows.go
index 9f40886d08b074ba47cd9f15c466547a891455d3..655f9348c62236f534a2c67aaff68548800b8b87 100644
--- a/src/internal/poll/fd_windows.go
+++ b/src/internal/poll/fd_windows.go
@@ -154,6 +154,10 @@ // IO in the current thread for systems where Windows CancelIoEx API
 // is available. Alternatively, it passes the request onto
 // runtime netpoll and waits for completion or cancels request.
 func (s *ioSrv) ExecIO(o *operation, submit func(o *operation) error) (int, error) {
+	if o.fd.pd.runtimeCtx == 0 {
+		return 0, errors.New("internal error: polling on unsupported descriptor type")
+	}
+
 	if !canCancelIO {
 		onceStartServer.Do(startServer)
 	}
@@ -315,8 +319,21 @@ 	default:
 		return "", errors.New("internal error: unknown network type " + net)
 	}
 
-	if err := fd.pd.init(fd); err != nil {
-		return "", err
+	if !fd.isFile && !fd.isConsole && !fd.isDir {
+		// Only call init for a network socket.
+		// This means that we don't add files to the runtime poller.
+		// Adding files to the runtime poller can confuse matters
+		// if the user is doing their own overlapped I/O.
+		// See issue #21172.
+		//
+		// In general the code below avoids calling the ExecIO
+		// method for non-network sockets. If some method does
+		// somehow call ExecIO, then ExecIO, and therefore the
+		// calling method, will return an error, because
+		// fd.pd.runtimeCtx will be 0.
+		if err := fd.pd.init(fd); err != nil {
+			return "", err
+		}
 	}
 	if hasLoadSetFileCompletionNotificationModes {
 		// We do not use events, so we can skip them always.
diff --git a/src/math/big/ratconv.go b/src/math/big/ratconv.go
index a6a401c857656942ab6d68edda91fe96adc172a1..4bc6ef7e8063edb648e20cf2187e17d3b40dd51c 100644
--- a/src/math/big/ratconv.go
+++ b/src/math/big/ratconv.go
@@ -40,8 +40,8 @@
 // SetString sets z to the value of s and returns z and a boolean indicating
 // success. s can be given as a fraction "a/b" or as a floating-point number
 // optionally followed by an exponent. The entire string (not just a prefix)
-// must be valid for success. If the operation failed, the value of z is un-
-// defined but the returned value is nil.
+// must be valid for success. If the operation failed, the value of z is
+// undefined but the returned value is nil.
 func (z *Rat) SetString(s string) (*Rat, bool) {
 	if len(s) == 0 {
 		return nil, false
diff --git a/src/math/bits/example_test.go b/src/math/bits/example_test.go
index 5d30f4b259970343cd1f977e62334f3ecce033fb..a43d1f365f60023d69538d5afe8123c20b4dbc02 100644
--- a/src/math/bits/example_test.go
+++ b/src/math/bits/example_test.go
@@ -36,3 +36,43 @@ 	// Output:
 	// 64
 	// 63
 }
+
+func ExampleOnesCount() {
+	fmt.Printf("%b\n", 14)
+	fmt.Println(bits.OnesCount(14))
+	// Output:
+	// 1110
+	// 3
+}
+
+func ExampleOnesCount8() {
+	fmt.Printf("%b\n", 14)
+	fmt.Println(bits.OnesCount8(14))
+	// Output:
+	// 1110
+	// 3
+}
+
+func ExampleOnesCount16() {
+	fmt.Printf("%b\n", 14)
+	fmt.Println(bits.OnesCount16(14))
+	// Output:
+	// 1110
+	// 3
+}
+
+func ExampleOnesCount32() {
+	fmt.Printf("%b\n", 14)
+	fmt.Println(bits.OnesCount32(14))
+	// Output:
+	// 1110
+	// 3
+}
+
+func ExampleOnesCount64() {
+	fmt.Printf("%b\n", 14)
+	fmt.Println(bits.OnesCount64(14))
+	// Output:
+	// 1110
+	// 3
+}
diff --git a/src/plugin/plugin.go b/src/plugin/plugin.go
index 3dc79640487ee3adb7895d45df5d80559cb340af..c7744658122a2b727730f55b40f3f6179d220910 100644
--- a/src/plugin/plugin.go
+++ b/src/plugin/plugin.go
@@ -4,8 +4,6 @@ // license that can be found in the LICENSE file.
 
 // Package plugin implements loading and symbol resolution of Go plugins.
 //
-// Currently plugins only work on Linux.
-//
 // A plugin is a Go main package with exported functions and variables that
 // has been built with:
 //
@@ -14,6 +12,9 @@ //
 // When a plugin is first opened, the init functions of all packages not
 // already part of the program are called. The main function is not run.
 // A plugin is only initialized once, and cannot be closed.
+//
+// The plugin support is currently incomplete, only supports Linux,
+// and has known bugs. Please report any issues.
 package plugin
 
 // Plugin is a loaded Go plugin.
diff --git a/src/reflect/deepequal.go b/src/reflect/deepequal.go
index f3fd7043e5acef020430c780c4abff90979fecdc..2fdd6a3d82ba35b31326d9a28c4bb23333d3eb8d 100644
--- a/src/reflect/deepequal.go
+++ b/src/reflect/deepequal.go
@@ -178,6 +178,12 @@ // is a sufficient condition to be deeply equal, regardless of content.
 // DeepEqual has been defined so that the same short-cut applies
 // to slices and maps: if x and y are the same slice or the same map,
 // they are deeply equal regardless of content.
+//
+// As DeepEqual traverses the data values it may find a cycle. The
+// second and subsequent times that DeepEqual compares two pointer
+// values that have been compared before, it treats the values as
+// equal rather than examining the values to which they point.
+// This ensures that DeepEqual terminates.
 func DeepEqual(x, y interface{}) bool {
 	if x == nil || y == nil {
 		return x == y
diff --git a/src/runtime/cpuprof.go b/src/runtime/cpuprof.go
index c761e440b66fc13acb749708f4fe62c75aaf7437..fb841a9f3ddcb12191a009c1cd3b703cc114cf38 100644
--- a/src/runtime/cpuprof.go
+++ b/src/runtime/cpuprof.go
@@ -163,6 +163,15 @@ 		cpuprof.log.write(nil, 0, hdr[:], lostStk[:])
 	}
 }
 
+func (p *cpuProfile) addLostAtomic64(count uint64) {
+	hdr := [1]uint64{count}
+	lostStk := [2]uintptr{
+		funcPC(_LostSIGPROFDuringAtomic64) + sys.PCQuantum,
+		funcPC(_System) + sys.PCQuantum,
+	}
+	cpuprof.log.write(nil, 0, hdr[:], lostStk[:])
+}
+
 // CPUProfile panics.
 // It formerly provided raw access to chunks of
 // a pprof-format profile generated by the runtime.
diff --git a/src/runtime/hashmap_fast.go b/src/runtime/hashmap_fast.go
index 1f9b313219c52c6a31696c2970219cb155d2ca44..67b978790989b05a3c262afc04bba7263d5e786f 100644
--- a/src/runtime/hashmap_fast.go
+++ b/src/runtime/hashmap_fast.go
@@ -495,7 +495,7 @@ 		val = add(insertk, bucketCnt*4)
 	}
 
 	// store new key/value at insert position
-	*((*uint32)(insertk)) = key
+	typedmemmove(t.key, insertk, unsafe.Pointer(&key))
 	*inserti = top
 	h.count++
 
@@ -583,7 +583,7 @@ 		val = add(insertk, bucketCnt*8)
 	}
 
 	// store new key/value at insert position
-	*((*uint64)(insertk)) = key
+	typedmemmove(t.key, insertk, unsafe.Pointer(&key))
 	*inserti = top
 	h.count++
 
@@ -723,7 +723,7 @@ 			k := (*uint32)(add(unsafe.Pointer(b), dataOffset+i*4))
 			if key != *k {
 				continue
 			}
-			*k = 0
+			typedmemclr(t.key, unsafe.Pointer(k))
 			v := unsafe.Pointer(uintptr(unsafe.Pointer(b)) + dataOffset + bucketCnt*4 + i*uintptr(t.valuesize))
 			typedmemclr(t.elem, v)
 			b.tophash[i] = empty
@@ -778,7 +778,7 @@ 			k := (*uint64)(add(unsafe.Pointer(b), dataOffset+i*8))
 			if key != *k {
 				continue
 			}
-			*k = 0
+			typedmemclr(t.key, unsafe.Pointer(k))
 			v := unsafe.Pointer(uintptr(unsafe.Pointer(b)) + dataOffset + bucketCnt*8 + i*uintptr(t.valuesize))
 			typedmemclr(t.elem, v)
 			b.tophash[i] = empty
diff --git a/src/runtime/pprof/pprof_test.go b/src/runtime/pprof/pprof_test.go
index 22fea0a52f1bab5327bef14f60871857fdba8987..992d2abb6a335c3c5ee253bc37720baea424e67c 100644
--- a/src/runtime/pprof/pprof_test.go
+++ b/src/runtime/pprof/pprof_test.go
@@ -12,6 +12,7 @@ 	"context"
 	"fmt"
 	"internal/testenv"
 	"io"
+	"io/ioutil"
 	"math/big"
 	"os"
 	"os/exec"
@@ -20,6 +21,7 @@ 	"runtime"
 	"runtime/pprof/internal/profile"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"testing"
 	"time"
 )
@@ -713,3 +715,32 @@ 			cpuHogger(cpuHog1, dur)
 		})
 	})
 }
+
+// Check that there is no deadlock when the program receives SIGPROF while in
+// 64bit atomics' critical section. Used to happen on mips{,le}. See #20146.
+func TestAtomicLoadStore64(t *testing.T) {
+	f, err := ioutil.TempFile("", "profatomic")
+	if err != nil {
+		t.Fatalf("TempFile: %v", err)
+	}
+	defer os.Remove(f.Name())
+	defer f.Close()
+
+	if err := StartCPUProfile(f); err != nil {
+		t.Fatal(err)
+	}
+	defer StopCPUProfile()
+
+	var flag uint64
+	done := make(chan bool, 1)
+
+	go func() {
+		for atomic.LoadUint64(&flag) == 0 {
+			runtime.Gosched()
+		}
+		done <- true
+	}()
+	time.Sleep(50 * time.Millisecond)
+	atomic.StoreUint64(&flag, 1)
+	<-done
+}
diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index a5ada4f6db4569be5dcd4a2103933e351b6d1887..ed333bb92eeeb915f4b376c56dd608ebb1cdd896 100644
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -3232,10 +3232,14 @@ 	signalLock uint32
 	hz         int32
 }
 
-func _System()           { _System() }
-func _ExternalCode()     { _ExternalCode() }
-func _LostExternalCode() { _LostExternalCode() }
-func _GC()               { _GC() }
+func _System()                    { _System() }
+func _ExternalCode()              { _ExternalCode() }
+func _LostExternalCode()          { _LostExternalCode() }
+func _GC()                        { _GC() }
+func _LostSIGPROFDuringAtomic64() { _LostSIGPROFDuringAtomic64() }
+
+// Counts SIGPROFs received while in atomic64 critical section, on mips{,le}
+var lostAtomic64Count uint64
 
 // Called if we receive a SIGPROF signal.
 // Called by the signal handler, may run during STW.
@@ -3243,6 +3247,21 @@ //go:nowritebarrierrec
 func sigprof(pc, sp, lr uintptr, gp *g, mp *m) {
 	if prof.hz == 0 {
 		return
+	}
+
+	// On mips{,le}, 64bit atomics are emulated with spinlocks, in
+	// runtime/internal/atomic. If SIGPROF arrives while the program is inside
+	// the critical section, it creates a deadlock (when writing the sample).
+	// As a workaround, create a counter of SIGPROFs while in critical section
+	// to store the count, and pass it to sigprof.add() later when SIGPROF is
+	// received from somewhere else (with _LostSIGPROFDuringAtomic64 as pc).
+	if GOARCH == "mips" || GOARCH == "mipsle" {
+		if f := findfunc(pc); f.valid() {
+			if hasprefix(funcname(f), "runtime/internal/atomic") {
+				lostAtomic64Count++
+				return
+			}
+		}
 	}
 
 	// Profiling runs concurrently with GC, so it must not allocate.
@@ -3371,6 +3390,10 @@ 		}
 	}
 
 	if prof.hz != 0 {
+		if (GOARCH == "mips" || GOARCH == "mipsle") && lostAtomic64Count > 0 {
+			cpuprof.addLostAtomic64(lostAtomic64Count)
+			lostAtomic64Count = 0
+		}
 		cpuprof.add(gp, stk[:n])
 	}
 	getg().m.mallocing--
diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go
index 8e410c456099e4facf12564242045c92821e6ba9..e1b41ca4ff8f029d132a5ce6c02ca8c4e2301549 100644
--- a/src/runtime/symtab.go
+++ b/src/runtime/symtab.go
@@ -409,6 +409,11 @@ // activeModules returns a slice of active modules.
 //
 // A module is active once its gcdatamask and gcbssmask have been
 // assembled and it is usable by the GC.
+//
+// This is nosplit/nowritebarrier because it is called by the
+// cgo pointer checking code.
+//go:nosplit
+//go:nowritebarrier
 func activeModules() []*moduledata {
 	p := (*[]*moduledata)(atomic.Loadp(unsafe.Pointer(&modulesSlice)))
 	if p == nil {
diff --git a/src/testing/testing.go b/src/testing/testing.go
index 3d1c0c694741dbe4d7c394c86a8fa1d428aa5a9c..11af926c80f8e9b69cc893c8317358c5057355bd 100644
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -970,7 +970,7 @@ 			fmt.Println(bench.Name)
 		}
 	}
 	for _, example := range examples {
-		if ok, _ := matchString(*matchList, example.Name); ok && example.Output != "" {
+		if ok, _ := matchString(*matchList, example.Name); ok {
 			fmt.Println(example.Name)
 		}
 	}
diff --git a/src/time/zoneinfo_windows_test.go b/src/time/zoneinfo_windows_test.go
index 7ac1e8682238ead39744b9d0368e3acf58670986..cf3b428c0956e9d707c92e4a931bb011b6029beb 100644
--- a/src/time/zoneinfo_windows_test.go
+++ b/src/time/zoneinfo_windows_test.go
@@ -14,6 +14,14 @@ func testZoneAbbr(t *testing.T) {
 	t1 := Now()
 	// discard nsec
 	t1 = Date(t1.Year(), t1.Month(), t1.Day(), t1.Hour(), t1.Minute(), t1.Second(), 0, t1.Location())
+
+	// Skip the test if we're in a timezone with no abbreviation.
+	// Format will fallback to the numeric abbreviation, and
+	// Parse(RFC1123, ..) will fail (see Issue 21183).
+	if tz := t1.Format("MST"); tz[0] == '-' || tz[0] == '+' {
+		t.Skip("No zone abbreviation")
+	}
+
 	t2, err := Parse(RFC1123, t1.Format(RFC1123))
 	if err != nil {
 		t.Fatalf("Parse failed: %v", err)
diff --git a/test/README.md b/test/README.md
new file mode 100644
index 0000000000000000000000000000000000000000..ca6a8c6580cfa66dbed86c307f6b105c585771e1
--- /dev/null
+++ b/test/README.md
@@ -0,0 +1,15 @@
+The test directory contains tests of the Go tool chain and runtime.
+It includes black box tests, regression tests, and error output tests.
+They are run as part of all.bash.
+
+To run just these tests, execute:
+
+    go run run.go
+
+Standard library tests should be written as regular Go tests in the appropriate package.
+
+The tool chain and runtime also have regular Go tests in their packages.
+The main reasons to add a new test to this directory are:
+
+* it is most naturally expressed using the test runner; or
+* it is also applicable to `gccgo` and other Go tool chains.
Moved GOROOT

Compiler Toolchain
