diff --git a/doc/go1.12.html b/doc/go1.12.html
index cc19c0f..7f0b221 100644
--- a/doc/go1.12.html
+++ b/doc/go1.12.html
@@ -80,6 +80,10 @@
   checks for private API usage. Since it is considered private,
   <code>syscall.Getdirentries</code> now always fails with
   <code>ENOSYS</code> on iOS.
+  Additionally, <a href="/pkg/syscall/#Setrlimit"><code>syscall.Setrlimit</code></a>
+  reports <code>invalid</code> <code>argument</code> in places where it historically
+  succeeded. These consequences are not specific to Go and users should expect
+  behavioral parity with <code>libSystem</code>'s implementation going forward.
 </p>
 
 <h2 id="tools">Tools</h2>
diff --git a/misc/cgo/testshared/shared_test.go b/misc/cgo/testshared/shared_test.go
index 41a24ef..1f426bb 100644
--- a/misc/cgo/testshared/shared_test.go
+++ b/misc/cgo/testshared/shared_test.go
@@ -917,3 +917,10 @@
 func TestGeneratedMethod(t *testing.T) {
 	goCmd(t, "install", "-buildmode=shared", "-linkshared", "issue25065")
 }
+
+// Test use of shared library struct with generated hash function.
+// Issue 30768.
+func TestGeneratedHash(t *testing.T) {
+	goCmd(nil, "install", "-buildmode=shared", "-linkshared", "issue30768/issue30768lib")
+	goCmd(nil, "test", "-linkshared", "issue30768")
+}
diff --git a/misc/cgo/testshared/src/issue30768/issue30768lib/lib.go b/misc/cgo/testshared/src/issue30768/issue30768lib/lib.go
new file mode 100644
index 0000000..9e45ebe
--- /dev/null
+++ b/misc/cgo/testshared/src/issue30768/issue30768lib/lib.go
@@ -0,0 +1,11 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package issue30768lib
+
+// S is a struct that requires a generated hash function.
+type S struct {
+	A string
+	B int
+}
diff --git a/misc/cgo/testshared/src/issue30768/x_test.go b/misc/cgo/testshared/src/issue30768/x_test.go
new file mode 100644
index 0000000..228da6f
--- /dev/null
+++ b/misc/cgo/testshared/src/issue30768/x_test.go
@@ -0,0 +1,22 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package issue30768_test
+
+import (
+	"testing"
+
+	"issue30768/issue30768lib"
+)
+
+type s struct {
+	s issue30768lib.S
+}
+
+func Test30768(t *testing.T) {
+	// Calling t.Log will convert S to an empty interface,
+	// which will force a reference to the generated hash function,
+	// defined in the shared library.
+	t.Log(s{})
+}
diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index 2cb7ae7..e63cf71 100644
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -1802,7 +1802,15 @@
 		if elf.ST_TYPE(elfsym.Info) == elf.STT_NOTYPE || elf.ST_TYPE(elfsym.Info) == elf.STT_SECTION {
 			continue
 		}
-		lsym := ctxt.Syms.Lookup(elfsym.Name, 0)
+
+		// Symbols whose names start with "type." are compiler
+		// generated, so make functions with that prefix internal.
+		ver := 0
+		if elf.ST_TYPE(elfsym.Info) == elf.STT_FUNC && strings.HasPrefix(elfsym.Name, "type.") {
+			ver = sym.SymVerABIInternal
+		}
+
+		lsym := ctxt.Syms.Lookup(elfsym.Name, ver)
 		// Because loadlib above loads all .a files before loading any shared
 		// libraries, any non-dynimport symbols we find that duplicate symbols
 		// already loaded should be ignored (the symbols from the .a files
@@ -1830,7 +1838,7 @@
 		// the ABIs are actually different. We might have to
 		// mangle Go function names in the .so to include the
 		// ABI.
-		if elf.ST_TYPE(elfsym.Info) == elf.STT_FUNC {
+		if elf.ST_TYPE(elfsym.Info) == elf.STT_FUNC && ver == 0 {
 			alias := ctxt.Syms.Lookup(elfsym.Name, sym.SymVerABIInternal)
 			if alias.Type != 0 {
 				continue
@@ -1958,7 +1966,7 @@
 		s.Attr |= sym.AttrStackCheck
 	}
 
-	if depth > 100 {
+	if depth > 500 {
 		Errorf(s, "nosplit stack check too deep")
 		stkbroke(ctxt, up, 0)
 		return -1
diff --git a/src/crypto/tls/tls_test.go b/src/crypto/tls/tls_test.go
index 208c13c..d7d1e2c 100644
--- a/src/crypto/tls/tls_test.go
+++ b/src/crypto/tls/tls_test.go
@@ -370,47 +370,6 @@
 	}
 }
 
-func TestVerifyHostnameResumed(t *testing.T) {
-	t.Run("TLSv12", func(t *testing.T) { testVerifyHostnameResumed(t, VersionTLS12) })
-	t.Run("TLSv13", func(t *testing.T) { testVerifyHostnameResumed(t, VersionTLS13) })
-}
-
-func testVerifyHostnameResumed(t *testing.T, version uint16) {
-	testenv.MustHaveExternalNetwork(t)
-
-	config := &Config{
-		MaxVersion:         version,
-		ClientSessionCache: NewLRUClientSessionCache(32),
-	}
-	for i := 0; i < 2; i++ {
-		c, err := Dial("tcp", "mail.google.com:https", config)
-		if err != nil {
-			t.Fatalf("Dial #%d: %v", i, err)
-		}
-		cs := c.ConnectionState()
-		if i > 0 && !cs.DidResume {
-			t.Fatalf("Subsequent connection unexpectedly didn't resume")
-		}
-		if cs.Version != version {
-			t.Fatalf("Unexpectedly negotiated version %x", cs.Version)
-		}
-		if cs.VerifiedChains == nil {
-			t.Fatalf("Dial #%d: cs.VerifiedChains == nil", i)
-		}
-		if err := c.VerifyHostname("mail.google.com"); err != nil {
-			t.Fatalf("verify mail.google.com #%d: %v", i, err)
-		}
-		// Give the client a chance to read the server session tickets.
-		c.SetReadDeadline(time.Now().Add(500 * time.Millisecond))
-		if _, err := c.Read(make([]byte, 1)); err != nil {
-			if err, ok := err.(net.Error); !ok || !err.Timeout() {
-				t.Fatal(err)
-			}
-		}
-		c.Close()
-	}
-}
-
 func TestConnCloseBreakingWrite(t *testing.T) {
 	ln := newLocalListener(t)
 	defer ln.Close()
diff --git a/src/math/big/arith_arm64.s b/src/math/big/arith_arm64.s
index eebdf59..98bdbc7 100644
--- a/src/math/big/arith_arm64.s
+++ b/src/math/big/arith_arm64.s
@@ -194,83 +194,97 @@
 	MOVD	R2, c+56(FP)
 	RET
 
-
 // func shlVU(z, x []Word, s uint) (c Word)
+// This implementation handles the shift operation from the high word to the low word,
+// which may be an error for the case where the low word of x overlaps with the high
+// word of z. When calling this function directly, you need to pay attention to this
+// situation.
 TEXT ·shlVU(SB),NOSPLIT,$0
-	MOVD	z+0(FP), R0
-	MOVD	z_len+8(FP), R1
+	LDP	z+0(FP), (R0, R1)	// R0 = z.ptr, R1 = len(z)
 	MOVD	x+24(FP), R2
 	MOVD	s+48(FP), R3
-	MOVD	$0, R8		// in order not to affect the first element, R8 is initialized to zero
-	MOVD	$64, R4
-	SUB	R3, R4
+	ADD	R1<<3, R0	// R0 = &z[n]
+	ADD	R1<<3, R2	// R2 = &x[n]
 	CBZ	R1, len0
 	CBZ	R3, copy	// if the number of shift is 0, just copy x to z
-
-	TBZ	$0, R1, two
-	MOVD.P	8(R2), R6
-	LSR	R4, R6, R8
-	LSL	R3, R6
-	MOVD.P	R6, 8(R0)
+	MOVD	$64, R4
+	SUB	R3, R4
+	// handling the most significant element x[n-1]
+	MOVD.W	-8(R2), R6
+	LSR	R4, R6, R5	// return value
+	LSL	R3, R6, R8	// x[i] << s
 	SUB	$1, R1
+one:	TBZ	$0, R1, two
+	MOVD.W	-8(R2), R6
+	LSR	R4, R6, R7
+	ORR	R8, R7
+	LSL	R3, R6, R8
+	SUB	$1, R1
+	MOVD.W	R7, -8(R0)
 two:
 	TBZ	$1, R1, loop
-	LDP.P	16(R2), (R6, R7)
-	LSR	R4, R6, R9
-	LSL	R3, R6
-	ORR	R8, R6
-	LSR	R4, R7, R8
+	LDP.W	-16(R2), (R6, R7)
+	LSR	R4, R7, R10
+	ORR	R8, R10
 	LSL	R3, R7
-	ORR	R9, R7
-	STP.P	(R6, R7), 16(R0)
+	LSR	R4, R6, R9
+	ORR	R7, R9
+	LSL	R3, R6, R8
 	SUB	$2, R1
+	STP.W	(R9, R10), -16(R0)
 loop:
 	CBZ	R1, done
-	LDP.P	32(R2), (R10, R11)
-	LDP	-16(R2), (R12, R13)
-	LSR	R4, R10, R20
-	LSL	R3, R10
-	ORR	R8, R10		// z[i] = (x[i] << s) | (x[i-1] >> (64 - s))
-	LSR	R4, R11, R21
-	LSL	R3, R11
-	ORR	R20, R11
-	LSR	R4, R12, R22
-	LSL	R3, R12
-	ORR	R21, R12
-	LSR	R4, R13, R8
+	LDP.W	-32(R2), (R10, R11)
+	LDP	16(R2), (R12, R13)
+	LSR	R4, R13, R23
+	ORR	R8, R23		// z[i] = (x[i] << s) | (x[i-1] >> (64 - s))
 	LSL	R3, R13
-	ORR	R22, R13
-	STP.P	(R10, R11), 32(R0)
-	STP	(R12, R13), -16(R0)
+	LSR	R4, R12, R22
+	ORR	R13, R22
+	LSL	R3, R12
+	LSR	R4, R11, R21
+	ORR	R12, R21
+	LSL	R3, R11
+	LSR	R4, R10, R20
+	ORR	R11, R20
+	LSL	R3, R10, R8
+	STP.W	(R20, R21), -32(R0)
+	STP	(R22, R23), 16(R0)
 	SUB	$4, R1
 	B	loop
 done:
-	MOVD	R8, c+56(FP)	// the part moved out from the last element
+	MOVD.W	R8, -8(R0)	// the first element x[0]
+	MOVD	R5, c+56(FP)	// the part moved out from x[n-1]
 	RET
 copy:
+	CMP	R0, R2
+	BEQ	len0
 	TBZ	$0, R1, ctwo
-	MOVD.P	8(R2), R3
-	MOVD.P	R3, 8(R0)
+	MOVD.W	-8(R2), R4
+	MOVD.W	R4, -8(R0)
 	SUB	$1, R1
 ctwo:
 	TBZ	$1, R1, cloop
-	LDP.P	16(R2), (R4, R5)
-	STP.P	(R4, R5), 16(R0)
+	LDP.W	-16(R2), (R4, R5)
+	STP.W	(R4, R5), -16(R0)
 	SUB	$2, R1
 cloop:
 	CBZ	R1, len0
-	LDP.P	32(R2), (R4, R5)
-	LDP	-16(R2), (R6, R7)
-	STP.P	(R4, R5), 32(R0)
-	STP	(R6, R7), -16(R0)
+	LDP.W	-32(R2), (R4, R5)
+	LDP	16(R2), (R6, R7)
+	STP.W	(R4, R5), -32(R0)
+	STP	(R6, R7), 16(R0)
 	SUB	$4, R1
 	B	cloop
 len0:
 	MOVD	$0, c+56(FP)
 	RET
 
-
 // func shrVU(z, x []Word, s uint) (c Word)
+// This implementation handles the shift operation from the low word to the high word,
+// which may be an error for the case where the high word of x overlaps with the low
+// word of z. When calling this function directly, you need to pay attention to this
+// situation.
 TEXT ·shrVU(SB),NOSPLIT,$0
 	MOVD	z+0(FP), R0
 	MOVD	z_len+8(FP), R1
@@ -330,6 +344,8 @@
 	MOVD	R8, (R0)	// deal with the last element
 	RET
 copy:
+	CMP	R0, R2
+	BEQ	len0
 	TBZ	$0, R1, ctwo
 	MOVD.P	8(R2), R3
 	MOVD.P	R3, 8(R0)
diff --git a/src/math/big/arith_test.go b/src/math/big/arith_test.go
index cf386b3..d812f75 100644
--- a/src/math/big/arith_test.go
+++ b/src/math/big/arith_test.go
@@ -255,6 +255,75 @@
 	}
 }
 
+type argVU struct {
+	d  []Word // d is a Word slice, the input parameters x and z come from this array.
+	l  uint   // l is the length of the input parameters x and z.
+	xp uint   // xp is the starting position of the input parameter x, x := d[xp:xp+l].
+	zp uint   // zp is the starting position of the input parameter z, z := d[zp:zp+l].
+	s  uint   // s is the shift number.
+	r  []Word // r is the expected output result z.
+	c  Word   // c is the expected return value.
+	m  string // message.
+}
+
+var argshlVU = []argVU{
+	// test cases for shlVU
+	{[]Word{1, _M, _M, _M, _M, _M, 3 << (_W - 2), 0}, 7, 0, 0, 1, []Word{2, _M - 1, _M, _M, _M, _M, 1<<(_W-1) + 1}, 1, "complete overlap of shlVU"},
+	{[]Word{1, _M, _M, _M, _M, _M, 3 << (_W - 2), 0, 0, 0, 0}, 7, 0, 3, 1, []Word{2, _M - 1, _M, _M, _M, _M, 1<<(_W-1) + 1}, 1, "partial overlap by half of shlVU"},
+	{[]Word{1, _M, _M, _M, _M, _M, 3 << (_W - 2), 0, 0, 0, 0, 0, 0, 0}, 7, 0, 6, 1, []Word{2, _M - 1, _M, _M, _M, _M, 1<<(_W-1) + 1}, 1, "partial overlap by 1 Word of shlVU"},
+	{[]Word{1, _M, _M, _M, _M, _M, 3 << (_W - 2), 0, 0, 0, 0, 0, 0, 0, 0}, 7, 0, 7, 1, []Word{2, _M - 1, _M, _M, _M, _M, 1<<(_W-1) + 1}, 1, "no overlap of shlVU"},
+}
+
+var argshrVU = []argVU{
+	// test cases for shrVU
+	{[]Word{0, 3, _M, _M, _M, _M, _M, 1 << (_W - 1)}, 7, 1, 1, 1, []Word{1<<(_W-1) + 1, _M, _M, _M, _M, _M >> 1, 1 << (_W - 2)}, 1 << (_W - 1), "complete overlap of shrVU"},
+	{[]Word{0, 0, 0, 0, 3, _M, _M, _M, _M, _M, 1 << (_W - 1)}, 7, 4, 1, 1, []Word{1<<(_W-1) + 1, _M, _M, _M, _M, _M >> 1, 1 << (_W - 2)}, 1 << (_W - 1), "partial overlap by half of shrVU"},
+	{[]Word{0, 0, 0, 0, 0, 0, 0, 3, _M, _M, _M, _M, _M, 1 << (_W - 1)}, 7, 7, 1, 1, []Word{1<<(_W-1) + 1, _M, _M, _M, _M, _M >> 1, 1 << (_W - 2)}, 1 << (_W - 1), "partial overlap by 1 Word of shrVU"},
+	{[]Word{0, 0, 0, 0, 0, 0, 0, 0, 3, _M, _M, _M, _M, _M, 1 << (_W - 1)}, 7, 8, 1, 1, []Word{1<<(_W-1) + 1, _M, _M, _M, _M, _M >> 1, 1 << (_W - 2)}, 1 << (_W - 1), "no overlap of shrVU"},
+}
+
+func testShiftFunc(t *testing.T, f func(z, x []Word, s uint) Word, a argVU) {
+	// save a.d for error message, or it will be overwritten.
+	b := make([]Word, len(a.d))
+	copy(b, a.d)
+	z := a.d[a.zp : a.zp+a.l]
+	x := a.d[a.xp : a.xp+a.l]
+	c := f(z, x, a.s)
+	for i, zi := range z {
+		if zi != a.r[i] {
+			t.Errorf("d := %v, %s(d[%d:%d], d[%d:%d], %d)\n\tgot z[%d] = %#x; want %#x", b, a.m, a.zp, a.zp+a.l, a.xp, a.xp+a.l, a.s, i, zi, a.r[i])
+			break
+		}
+	}
+	if c != a.c {
+		t.Errorf("d := %v, %s(d[%d:%d], d[%d:%d], %d)\n\tgot c = %#x; want %#x", b, a.m, a.zp, a.zp+a.l, a.xp, a.xp+a.l, a.s, c, a.c)
+	}
+}
+
+func TestShiftOverlap(t *testing.T) {
+	for _, a := range argshlVU {
+		arg := a
+		testShiftFunc(t, shlVU, arg)
+	}
+
+	for _, a := range argshrVU {
+		arg := a
+		testShiftFunc(t, shrVU, arg)
+	}
+}
+
+func TestIssue31084(t *testing.T) {
+	// compute 10^n via 5^n << n.
+	const n = 165
+	p := nat(nil).expNN(nat{5}, nat{n}, nil)
+	p = p.shl(p, uint(n))
+	got := string(p.utoa(10))
+	want := "1" + strings.Repeat("0", n)
+	if got != want {
+		t.Errorf("shl(%v, %v)\n\tgot %s; want %s\n", p, uint(n), got, want)
+	}
+}
+
 func BenchmarkAddVW(b *testing.B) {
 	for _, n := range benchSizes {
 		if isRaceBuilder && n > 1e3 {
diff --git a/src/os/removeall_at.go b/src/os/removeall_at.go
index 330963b..c7de8a3 100644
--- a/src/os/removeall_at.go
+++ b/src/os/removeall_at.go
@@ -157,7 +157,7 @@
 	var r int
 	for {
 		var e error
-		r, e = unix.Openat(dirfd, name, O_RDONLY, 0)
+		r, e = unix.Openat(dirfd, name, O_RDONLY|syscall.O_CLOEXEC, 0)
 		if e == nil {
 			break
 		}
diff --git a/test/fixedbugs/issue33555.go b/test/fixedbugs/issue33555.go
new file mode 100644
index 0000000..7debd20
--- /dev/null
+++ b/test/fixedbugs/issue33555.go
@@ -0,0 +1,81 @@
+// +build !nacl,!js
+// run
+
+// 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.
+
+// Test that the linker permits long call sequences.
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+)
+
+const start = `
+package main
+
+func main() {
+	println(f0() + 1)
+}
+`
+
+const fn = `
+//go:noinline
+func f%d() int {
+	return f%d() + 1
+}`
+
+const fnlast = `
+//go:noinline
+func f%d() int {
+	return 0
+}
+`
+
+const count = 400
+
+func main() {
+	if err := test(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func test() error {
+	var buf bytes.Buffer
+	buf.WriteString(start)
+	for i := 0; i < count; i++ {
+		fmt.Fprintf(&buf, fn, i, i + 1)
+	}
+	fmt.Fprintf(&buf, fnlast, count)
+
+	dir, err := ioutil.TempDir("", "issue33555")
+	if err != nil {
+		return err
+	}
+	defer os.RemoveAll(dir)
+
+	fn := filepath.Join(dir, "x.go")
+	if err := ioutil.WriteFile(fn, buf.Bytes(), 0644); err != nil {
+		return err
+	}
+
+	out, err := exec.Command("go", "run", fn).CombinedOutput()
+	if err != nil {
+		return err
+	}
+
+	want := strconv.Itoa(count + 1)
+	if got := string(bytes.TrimSpace(out)); got != want {
+		return fmt.Errorf("got %q want %q", got, want)
+	}
+
+	return nil
+}