libgo: update to Go 1.11

    
    Reviewed-on: https://go-review.googlesource.com/136435

gotools/:
	* Makefile.am (mostlyclean-local): Run chmod on check-go-dir to
	make sure it is writable.
	(check-go-tools): Likewise.
	(check-vet): Copy internal/objabi to check-vet-dir.
	* Makefile.in: Rebuild.

From-SVN: r264546

62 files changed, 2306 insertions, 259 deletions

diff --git a/libgo/go/internal/bytealg/bytealg.c b/libgo/go/internal/bytealg/bytealg.c
new file mode 100644
index 0000000..39c060f
--- /dev/null
+++ b/libgo/go/internal/bytealg/bytealg.c
@@ -0,0 +1,116 @@
+/* bytealg.c -- gccgo implementations of bytealg functions
+
+   Copyright 2018 The Go Authors. All rights reserved.
+   Use of this source code is governed by a BSD-style
+   license that can be found in the LICENSE file.  */
+
+#include <stddef.h>
+#include <string.h>
+
+#include "runtime.h"
+#include "array.h"
+
+intgo Compare(struct __go_open_array, struct __go_open_array)
+  __asm__(GOSYM_PREFIX "internal_bytealg.Compare")
+  __attribute__((no_split_stack));
+
+intgo Compare(struct __go_open_array a, struct __go_open_array b)
+{
+	intgo l;
+
+	l = a.__count;
+	if (b.__count < l) {
+		l = b.__count;
+	}
+	if (l > 0 && a.__values != b.__values) {
+		int i;
+
+		i = __builtin_memcmp(a.__values, b.__values, (size_t)(l));
+		if (i != 0) {
+			return i;
+		}
+	}
+	if (a.__count < b.__count) {
+		return -1;
+	}
+	if (a.__count > b.__count) {
+		return +1;
+	}
+	return 0;
+}
+
+_Bool Equal(struct __go_open_array, struct __go_open_array)
+  __asm__(GOSYM_PREFIX "internal_bytealg.Equal")
+  __attribute__((no_split_stack));
+
+_Bool Equal(struct __go_open_array a, struct __go_open_array b)
+{
+	intgo l;
+
+	l = a.__count;
+	if (l != b.__count) {
+		return 0;
+	}
+	return __builtin_memcmp(a.__values, b.__values, l) == 0;
+}
+
+intgo IndexByte(struct __go_open_array, byte)
+  __asm__(GOSYM_PREFIX "internal_bytealg.IndexByte")
+  __attribute__((no_split_stack));
+
+intgo IndexByte(struct __go_open_array b, byte c)
+{
+	const byte *p;
+
+	p = __builtin_memchr(b.__values, c, (size_t)(b.__count));
+	if (p == nil) {
+		return -1;
+	}
+	return p - (byte *)(b.__values);
+}
+
+
+intgo IndexByteString(String, byte)
+  __asm__(GOSYM_PREFIX "internal_bytealg.IndexByteString")
+  __attribute__((no_split_stack));
+
+intgo IndexByteString(String s, byte c)
+{
+	const byte *p;
+
+	p = __builtin_memchr(s.str, c, (size_t)(s.len));
+	if (p == nil) {
+		return -1;
+	}
+	return p - s.str;
+}
+
+intgo Index(struct __go_open_array, struct __go_open_array)
+  __asm__(GOSYM_PREFIX "internal_bytealg.Index")
+  __attribute__((no_split_stack));
+
+intgo Index(struct __go_open_array a, struct __go_open_array b)
+{
+	const byte* p;
+
+	p = memmem(a.__values, a.__count, b.__values, b.__count);
+	if (p == nil) {
+		return -1;
+	}
+	return p - (const byte*)(a.__values);
+}
+
+intgo IndexString(String, String)
+  __asm__(GOSYM_PREFIX "internal_bytealg.IndexString")
+  __attribute__((no_split_stack));
+
+intgo IndexString(String a, String b)
+{
+	const byte* p;
+
+	p = memmem(a.str, a.len, b.str, b.len);
+	if (p == nil) {
+		return -1;
+	}
+	return p - a.str;
+}
diff --git a/libgo/go/internal/bytealg/bytealg.go b/libgo/go/internal/bytealg/bytealg.go
new file mode 100644
index 0000000..b91eb00
--- /dev/null
+++ b/libgo/go/internal/bytealg/bytealg.go
@@ -0,0 +1,24 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore_for_gccgo
+
+package bytealg
+
+import (
+	"internal/cpu"
+	"unsafe"
+)
+
+// Offsets into internal/cpu records for use in assembly.
+const (
+	x86_HasSSE2   = unsafe.Offsetof(cpu.X86.HasSSE2)
+	x86_HasSSE42  = unsafe.Offsetof(cpu.X86.HasSSE42)
+	x86_HasAVX2   = unsafe.Offsetof(cpu.X86.HasAVX2)
+	x86_HasPOPCNT = unsafe.Offsetof(cpu.X86.HasPOPCNT)
+	s390x_HasVX   = unsafe.Offsetof(cpu.S390X.HasVX)
+)
+
+// MaxLen is the maximum length of the string to be searched for (argument b) in Index.
+var MaxLen int = 32
diff --git a/libgo/go/internal/bytealg/compare_generic.go b/libgo/go/internal/bytealg/compare_generic.go
new file mode 100644
index 0000000..bb48833
--- /dev/null
+++ b/libgo/go/internal/bytealg/compare_generic.go
@@ -0,0 +1,89 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore_for_gccgo
+// +build !386,!amd64,!amd64p32,!s390x,!arm,!arm64,!ppc64,!ppc64le,!mips,!mipsle,!wasm
+
+package bytealg
+
+import _ "unsafe" // for go:linkname
+
+func Compare(a, b []byte) int {
+	l := len(a)
+	if len(b) < l {
+		l = len(b)
+	}
+	if l == 0 || &a[0] == &b[0] {
+		goto samebytes
+	}
+	for i := 0; i < l; i++ {
+		c1, c2 := a[i], b[i]
+		if c1 < c2 {
+			return -1
+		}
+		if c1 > c2 {
+			return +1
+		}
+	}
+samebytes:
+	if len(a) < len(b) {
+		return -1
+	}
+	if len(a) > len(b) {
+		return +1
+	}
+	return 0
+}
+
+//go:linkname bytes_Compare bytes.Compare
+func bytes_Compare(a, b []byte) int {
+	l := len(a)
+	if len(b) < l {
+		l = len(b)
+	}
+	if l == 0 || &a[0] == &b[0] {
+		goto samebytes
+	}
+	for i := 0; i < l; i++ {
+		c1, c2 := a[i], b[i]
+		if c1 < c2 {
+			return -1
+		}
+		if c1 > c2 {
+			return +1
+		}
+	}
+samebytes:
+	if len(a) < len(b) {
+		return -1
+	}
+	if len(a) > len(b) {
+		return +1
+	}
+	return 0
+}
+
+//go:linkname runtime_cmpstring runtime.cmpstring
+func runtime_cmpstring(a, b string) int {
+	l := len(a)
+	if len(b) < l {
+		l = len(b)
+	}
+	for i := 0; i < l; i++ {
+		c1, c2 := a[i], b[i]
+		if c1 < c2 {
+			return -1
+		}
+		if c1 > c2 {
+			return +1
+		}
+	}
+	if len(a) < len(b) {
+		return -1
+	}
+	if len(a) > len(b) {
+		return +1
+	}
+	return 0
+}
diff --git a/libgo/go/internal/bytealg/compare_native.go b/libgo/go/internal/bytealg/compare_native.go
new file mode 100644
index 0000000..2c317e2
--- /dev/null
+++ b/libgo/go/internal/bytealg/compare_native.go
@@ -0,0 +1,10 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// -build 386 amd64 amd64p32 s390x arm arm64 ppc64 ppc64le mips mipsle wasm
+
+package bytealg
+
+//go:noescape
+func Compare(a, b []byte) int
diff --git a/libgo/go/internal/bytealg/count_generic.go b/libgo/go/internal/bytealg/count_generic.go
new file mode 100644
index 0000000..5a06430
--- /dev/null
+++ b/libgo/go/internal/bytealg/count_generic.go
@@ -0,0 +1,27 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// -build !amd64,!arm64
+
+package bytealg
+
+func Count(b []byte, c byte) int {
+	n := 0
+	for _, x := range b {
+		if x == c {
+			n++
+		}
+	}
+	return n
+}
+
+func CountString(s string, c byte) int {
+	n := 0
+	for i := 0; i < len(s); i++ {
+		if s[i] == c {
+			n++
+		}
+	}
+	return n
+}
diff --git a/libgo/go/internal/bytealg/count_native.go b/libgo/go/internal/bytealg/count_native.go
new file mode 100644
index 0000000..5ea5c28
--- /dev/null
+++ b/libgo/go/internal/bytealg/count_native.go
@@ -0,0 +1,34 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore_for_gccgo
+// +build amd64 arm64
+
+package bytealg
+
+//go:noescape
+func Count(b []byte, c byte) int
+
+//go:noescape
+func CountString(s string, c byte) int
+
+// A backup implementation to use by assembly.
+func countGeneric(b []byte, c byte) int {
+	n := 0
+	for _, x := range b {
+		if x == c {
+			n++
+		}
+	}
+	return n
+}
+func countGenericString(s string, c byte) int {
+	n := 0
+	for i := 0; i < len(s); i++ {
+		if s[i] == c {
+			n++
+		}
+	}
+	return n
+}
diff --git a/libgo/go/internal/bytealg/equal_native.go b/libgo/go/internal/bytealg/equal_native.go
new file mode 100644
index 0000000..b5c4530
--- /dev/null
+++ b/libgo/go/internal/bytealg/equal_native.go
@@ -0,0 +1,14 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bytealg
+
+// Note: there's no equal_generic.go because every platform must implement at least memequal_varlen in assembly.
+
+//go:noescape
+func Equal(a, b []byte) bool
+
+// The compiler generates calls to runtime.memequal and runtime.memequal_varlen.
+// In addition, the runtime calls runtime.memequal explicitly.
+// Those functions are implemented in this package.
diff --git a/libgo/go/internal/bytealg/gccgo.go b/libgo/go/internal/bytealg/gccgo.go
new file mode 100644
index 0000000..8c78b63
--- /dev/null
+++ b/libgo/go/internal/bytealg/gccgo.go
@@ -0,0 +1,12 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build gccgo
+
+package bytealg
+
+// MaxLen is the maximum length of the string to be searched for (argument b) in Index.
+var MaxLen int = 32
+
+const MaxBruteForce = 64
diff --git a/libgo/go/internal/bytealg/index_amd64.go b/libgo/go/internal/bytealg/index_amd64.go
new file mode 100644
index 0000000..dd6a6cf
--- /dev/null
+++ b/libgo/go/internal/bytealg/index_amd64.go
@@ -0,0 +1,28 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore_for_gccgo
+
+package bytealg
+
+import "internal/cpu"
+
+const MaxBruteForce = 64
+
+func init() {
+	if cpu.X86.HasAVX2 {
+		MaxLen = 63
+	} else {
+		MaxLen = 31
+	}
+}
+
+// Cutover reports the number of failures of IndexByte we should tolerate
+// before switching over to Index.
+// n is the number of bytes processed so far.
+// See the bytes.Index implementation for details.
+func Cutover(n int) int {
+	// 1 error per 8 characters, plus a few slop to start.
+	return (n + 16) / 8
+}
diff --git a/libgo/go/internal/bytealg/index_arm64.go b/libgo/go/internal/bytealg/index_arm64.go
new file mode 100644
index 0000000..51bdf16
--- /dev/null
+++ b/libgo/go/internal/bytealg/index_arm64.go
@@ -0,0 +1,25 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore_for_gccgo
+
+package bytealg
+
+// Empirical data shows that using IndexShortStr can get better
+// performance when len(s) <= 16.
+const MaxBruteForce = 16
+
+func init() {
+	// Optimize cases where the length of the substring is less than 32 bytes
+	MaxLen = 32
+}
+
+// Cutover reports the number of failures of IndexByte we should tolerate
+// before switching over to IndexShortStr.
+// n is the number of bytes processed so far.
+// See the bytes.Index implementation for details.
+func Cutover(n int) int {
+	// 1 error per 16 characters, plus a few slop to start.
+	return 4 + n>>4
+}
diff --git a/libgo/go/internal/bytealg/index_generic.go b/libgo/go/internal/bytealg/index_generic.go
new file mode 100644
index 0000000..c595c23
--- /dev/null
+++ b/libgo/go/internal/bytealg/index_generic.go
@@ -0,0 +1,30 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore_for_gccgo
+// +build !amd64,!arm64,!s390x
+
+package bytealg
+
+const MaxBruteForce = 0
+
+// Index returns the index of the first instance of b in a, or -1 if b is not present in a.
+// Requires 2 <= len(b) <= MaxLen.
+func Index(a, b []byte) int {
+	panic("unimplemented")
+}
+
+// IndexString returns the index of the first instance of b in a, or -1 if b is not present in a.
+// Requires 2 <= len(b) <= MaxLen.
+func IndexString(a, b string) int {
+	panic("unimplemented")
+}
+
+// Cutover reports the number of failures of IndexByte we should tolerate
+// before switching over to Index.
+// n is the number of bytes processed so far.
+// See the bytes.Index implementation for details.
+func Cutover(n int) int {
+	panic("unimplemented")
+}
diff --git a/libgo/go/internal/bytealg/index_native.go b/libgo/go/internal/bytealg/index_native.go
new file mode 100644
index 0000000..26f4769
--- /dev/null
+++ b/libgo/go/internal/bytealg/index_native.go
@@ -0,0 +1,24 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// -build amd64 arm64 s390x
+
+package bytealg
+
+//go:noescape
+
+// Index returns the index of the first instance of b in a, or -1 if b is not present in a.
+// Requires 2 <= len(b) <= MaxLen.
+func Index(a, b []byte) int
+
+//go:noescape
+
+// IndexString returns the index of the first instance of b in a, or -1 if b is not present in a.
+// Requires 2 <= len(b) <= MaxLen.
+func IndexString(a, b string) int
+
+func Cutover(n int) int {
+	// 1 error per 8 characters, plus a few slop to start.
+	return (n + 16) / 8
+}
diff --git a/libgo/go/internal/bytealg/index_s390x.go b/libgo/go/internal/bytealg/index_s390x.go
new file mode 100644
index 0000000..ee076a0
--- /dev/null
+++ b/libgo/go/internal/bytealg/index_s390x.go
@@ -0,0 +1,33 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore_for_gcco
+
+package bytealg
+
+import "internal/cpu"
+
+const MaxBruteForce = 64
+
+func init() {
+	// Note: we're kind of lucky that this flag is available at this point.
+	// The runtime sets HasVX when processing auxv records, and that happens
+	// to happen *before* running the init functions of packages that
+	// the runtime depends on.
+	// TODO: it would really be nicer for internal/cpu to figure out this
+	// flag by itself. Then we wouldn't need to depend on quirks of
+	// early startup initialization order.
+	if cpu.S390X.HasVX {
+		MaxLen = 64
+	}
+}
+
+// Cutover reports the number of failures of IndexByte we should tolerate
+// before switching over to Index.
+// n is the number of bytes processed so far.
+// See the bytes.Index implementation for details.
+func Cutover(n int) int {
+	// 1 error per 8 characters, plus a few slop to start.
+	return (n + 16) / 8
+}
diff --git a/libgo/go/internal/bytealg/indexbyte_generic.go b/libgo/go/internal/bytealg/indexbyte_generic.go
new file mode 100644
index 0000000..890cd42
--- /dev/null
+++ b/libgo/go/internal/bytealg/indexbyte_generic.go
@@ -0,0 +1,48 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +ignore_for_gccgo
+// +build !386,!amd64,!amd64p32,!s390x,!arm,!arm64,!ppc64,!ppc64le,!mips,!mipsle,!mips64,!mips64le,!wasm
+
+package bytealg
+
+import _ "unsafe" // for go:linkname
+
+func IndexByte(b []byte, c byte) int {
+	for i, x := range b {
+		if x == c {
+			return i
+		}
+	}
+	return -1
+}
+
+func IndexByteString(s string, c byte) int {
+	for i := 0; i < len(s); i++ {
+		if s[i] == c {
+			return i
+		}
+	}
+	return -1
+}
+
+//go:linkname bytes_IndexByte bytes.IndexByte
+func bytes_IndexByte(b []byte, c byte) int {
+	for i, x := range b {
+		if x == c {
+			return i
+		}
+	}
+	return -1
+}
+
+//go:linkname strings_IndexByte strings.IndexByte
+func strings_IndexByte(s string, c byte) int {
+	for i := 0; i < len(s); i++ {
+		if s[i] == c {
+			return i
+		}
+	}
+	return -1
+}
diff --git a/libgo/go/internal/bytealg/indexbyte_native.go b/libgo/go/internal/bytealg/indexbyte_native.go
new file mode 100644
index 0000000..5cf6fed
--- /dev/null
+++ b/libgo/go/internal/bytealg/indexbyte_native.go
@@ -0,0 +1,13 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// -build 386 amd64 amd64p32 s390x arm arm64 ppc64 ppc64le mips mipsle mips64 mips64le wasm
+
+package bytealg
+
+//go:noescape
+func IndexByte(b []byte, c byte) int
+
+//go:noescape
+func IndexByteString(s string, c byte) int
diff --git a/libgo/go/internal/cpu/cpu.go b/libgo/go/internal/cpu/cpu.go
index 22fc561..9567a4f 100644
--- a/libgo/go/internal/cpu/cpu.go
+++ b/libgo/go/internal/cpu/cpu.go
@@ -6,6 +6,11 @@
 // used by the Go standard library.
 package cpu
 
+// DebugOptions is set to true by the runtime if go was compiled with GOEXPERIMENT=debugcpu
+// and GOOS is Linux or Darwin.
+// This should not be changed after it is initialized.
+var DebugOptions bool
+
 var X86 x86
 
 // The booleans in x86 contain the correspondingly named cpuid feature bit.
@@ -37,9 +42,9 @@ var PPC64 ppc64
 
 // For ppc64x, it is safe to check only for ISA level starting on ISA v3.00,
 // since there are no optional categories. There are some exceptions that also
-// require kernel support to work (darn, scv), so there are capability bits for
+// require kernel support to work (darn, scv), so there are feature bits for
 // those as well. The minimum processor requirement is POWER8 (ISA 2.07), so we
-// maintain some of the old capability checks for optional categories for
+// maintain some of the old feature checks for optional categories for
 // safety.
 // The struct is padded to avoid false sharing.
 type ppc64 struct {
@@ -63,15 +68,126 @@ var ARM64 arm64
 // The booleans in arm64 contain the correspondingly named cpu feature bit.
 // The struct is padded to avoid false sharing.
 type arm64 struct {
-	_          [CacheLineSize]byte
-	HasFP      bool
-	HasASIMD   bool
-	HasEVTSTRM bool
-	HasAES     bool
-	HasPMULL   bool
-	HasSHA1    bool
-	HasSHA2    bool
-	HasCRC32   bool
-	HasATOMICS bool
-	_          [CacheLineSize]byte
+	_           [CacheLineSize]byte
+	HasFP       bool
+	HasASIMD    bool
+	HasEVTSTRM  bool
+	HasAES      bool
+	HasPMULL    bool
+	HasSHA1     bool
+	HasSHA2     bool
+	HasCRC32    bool
+	HasATOMICS  bool
+	HasFPHP     bool
+	HasASIMDHP  bool
+	HasCPUID    bool
+	HasASIMDRDM bool
+	HasJSCVT    bool
+	HasFCMA     bool
+	HasLRCPC    bool
+	HasDCPOP    bool
+	HasSHA3     bool
+	HasSM3      bool
+	HasSM4      bool
+	HasASIMDDP  bool
+	HasSHA512   bool
+	HasSVE      bool
+	HasASIMDFHM bool
+	_           [CacheLineSize]byte
+}
+
+var S390X s390x
+
+type s390x struct {
+	_               [CacheLineSize]byte
+	HasZArch        bool // z architecture mode is active [mandatory]
+	HasSTFLE        bool // store facility list extended [mandatory]
+	HasLDisp        bool // long (20-bit) displacements [mandatory]
+	HasEImm         bool // 32-bit immediates [mandatory]
+	HasDFP          bool // decimal floating point
+	HasETF3Enhanced bool // ETF-3 enhanced
+	HasMSA          bool // message security assist (CPACF)
+	HasAES          bool // KM-AES{128,192,256} functions
+	HasAESCBC       bool // KMC-AES{128,192,256} functions
+	HasAESCTR       bool // KMCTR-AES{128,192,256} functions
+	HasAESGCM       bool // KMA-GCM-AES{128,192,256} functions
+	HasGHASH        bool // KIMD-GHASH function
+	HasSHA1         bool // K{I,L}MD-SHA-1 functions
+	HasSHA256       bool // K{I,L}MD-SHA-256 functions
+	HasSHA512       bool // K{I,L}MD-SHA-512 functions
+	HasVX           bool // vector facility. Note: the runtime sets this when it processes auxv records.
+	_               [CacheLineSize]byte
+}
+
+// Initialize examines the processor and sets the relevant variables above.
+// This is called by the runtime package early in program initialization,
+// before normal init functions are run. env is set by runtime on Linux and Darwin
+// if go was compiled with GOEXPERIMENT=debugcpu.
+func Initialize(env string) {
+	doinit()
+	processOptions(env)
+}
+
+// options contains the cpu debug options that can be used in GODEBUGCPU.
+// Options are arch dependent and are added by the arch specific doinit functions.
+// Features that are mandatory for the specific GOARCH should not be added to options
+// (e.g. SSE2 on amd64).
+var options []option
+
+// Option names should be lower case. e.g. avx instead of AVX.
+type option struct {
+	Name    string
+	Feature *bool
+}
+
+// processOptions disables CPU feature values based on the parsed env string.
+// The env string is expected to be of the form feature1=0,feature2=0...
+// where feature names is one of the architecture specifc list stored in the
+// cpu packages options variable. If env contains all=0 then all capabilities
+// referenced through the options variable are disabled. Other feature
+// names and values other than 0 are silently ignored.
+func processOptions(env string) {
+field:
+	for env != "" {
+		field := ""
+		i := indexByte(env, ',')
+		if i < 0 {
+			field, env = env, ""
+		} else {
+			field, env = env[:i], env[i+1:]
+		}
+		i = indexByte(field, '=')
+		if i < 0 {
+			continue
+		}
+		key, value := field[:i], field[i+1:]
+
+		// Only allow turning off CPU features by specifying '0'.
+		if value == "0" {
+			if key == "all" {
+				for _, v := range options {
+					*v.Feature = false
+				}
+				return
+			} else {
+				for _, v := range options {
+					if v.Name == key {
+						*v.Feature = false
+						continue field
+					}
+				}
+			}
+		}
+	}
+}
+
+// indexByte returns the index of the first instance of c in s,
+// or -1 if c is not present in s.
+func indexByte(s string, c byte) int {
+	for i := 0; i < len(s); i++ {
+		if s[i] == c {
+			return i
+		}
+	}
+	return -1
 }
diff --git a/libgo/go/internal/cpu/cpu_386.go b/libgo/go/internal/cpu/cpu_386.go
new file mode 100644
index 0000000..561c81f
--- /dev/null
+++ b/libgo/go/internal/cpu/cpu_386.go
@@ -0,0 +1,7 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cpu
+
+const GOARCH = "386"
diff --git a/libgo/go/internal/cpu/cpu_amd64.go b/libgo/go/internal/cpu/cpu_amd64.go
new file mode 100644
index 0000000..9b00153
--- /dev/null
+++ b/libgo/go/internal/cpu/cpu_amd64.go
@@ -0,0 +1,7 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cpu
+
+const GOARCH = "amd64"
diff --git a/libgo/go/internal/cpu/cpu_amd64p32.go b/libgo/go/internal/cpu/cpu_amd64p32.go
new file mode 100644
index 0000000..177b14e
--- /dev/null
+++ b/libgo/go/internal/cpu/cpu_amd64p32.go
@@ -0,0 +1,7 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cpu
+
+const GOARCH = "amd64p32"
diff --git a/libgo/go/internal/cpu/cpu_arm64.go b/libgo/go/internal/cpu/cpu_arm64.go
index e1278a1..009f2a2 100644
--- a/libgo/go/internal/cpu/cpu_arm64.go
+++ b/libgo/go/internal/cpu/cpu_arm64.go
@@ -2,42 +2,99 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build arm64
-
 package cpu
 
 const CacheLineSize = 64
 
 // arm64 doesn't have a 'cpuid' equivalent, so we rely on HWCAP/HWCAP2.
-// These are linknamed in runtime/os_linux_arm64.go and are initialized by
-// archauxv().
-var arm64_hwcap uint
-var arm64_hwcap2 uint
+// These are initialized by archauxv in runtime/os_linux_arm64.go.
+// These should not be changed after they are initialized.
+var HWCap uint
+var HWCap2 uint
 
 // HWCAP/HWCAP2 bits. These are exposed by Linux.
 const (
-	_ARM64_FEATURE_HAS_FP      = (1 << 0)
-	_ARM64_FEATURE_HAS_ASIMD   = (1 << 1)
-	_ARM64_FEATURE_HAS_EVTSTRM = (1 << 2)
-	_ARM64_FEATURE_HAS_AES     = (1 << 3)
-	_ARM64_FEATURE_HAS_PMULL   = (1 << 4)
-	_ARM64_FEATURE_HAS_SHA1    = (1 << 5)
-	_ARM64_FEATURE_HAS_SHA2    = (1 << 6)
-	_ARM64_FEATURE_HAS_CRC32   = (1 << 7)
-	_ARM64_FEATURE_HAS_ATOMICS = (1 << 8)
+	hwcap_FP       = (1 << 0)
+	hwcap_ASIMD    = (1 << 1)
+	hwcap_EVTSTRM  = (1 << 2)
+	hwcap_AES      = (1 << 3)
+	hwcap_PMULL    = (1 << 4)
+	hwcap_SHA1     = (1 << 5)
+	hwcap_SHA2     = (1 << 6)
+	hwcap_CRC32    = (1 << 7)
+	hwcap_ATOMICS  = (1 << 8)
+	hwcap_FPHP     = (1 << 9)
+	hwcap_ASIMDHP  = (1 << 10)
+	hwcap_CPUID    = (1 << 11)
+	hwcap_ASIMDRDM = (1 << 12)
+	hwcap_JSCVT    = (1 << 13)
+	hwcap_FCMA     = (1 << 14)
+	hwcap_LRCPC    = (1 << 15)
+	hwcap_DCPOP    = (1 << 16)
+	hwcap_SHA3     = (1 << 17)
+	hwcap_SM3      = (1 << 18)
+	hwcap_SM4      = (1 << 19)
+	hwcap_ASIMDDP  = (1 << 20)
+	hwcap_SHA512   = (1 << 21)
+	hwcap_SVE      = (1 << 22)
+	hwcap_ASIMDFHM = (1 << 23)
 )
 
-func init() {
+func doinit() {
+	options = []option{
+		{"evtstrm", &ARM64.HasEVTSTRM},
+		{"aes", &ARM64.HasAES},
+		{"pmull", &ARM64.HasPMULL},
+		{"sha1", &ARM64.HasSHA1},
+		{"sha2", &ARM64.HasSHA2},
+		{"crc32", &ARM64.HasCRC32},
+		{"atomics", &ARM64.HasATOMICS},
+		{"fphp", &ARM64.HasFPHP},
+		{"asimdhp", &ARM64.HasASIMDHP},
+		{"cpuid", &ARM64.HasCPUID},
+		{"asimdrdm", &ARM64.HasASIMDRDM},
+		{"jscvt", &ARM64.HasJSCVT},
+		{"fcma", &ARM64.HasFCMA},
+		{"lrcpc", &ARM64.HasLRCPC},
+		{"dcpop", &ARM64.HasDCPOP},
+		{"sha3", &ARM64.HasSHA3},
+		{"sm3", &ARM64.HasSM3},
+		{"sm4", &ARM64.HasSM4},
+		{"asimddp", &ARM64.HasASIMDDP},
+		{"sha512", &ARM64.HasSHA512},
+		{"sve", &ARM64.HasSVE},
+		{"asimdfhm", &ARM64.HasASIMDFHM},
+
+		// These capabilities should always be enabled on arm64:
+		//  {"fp", &ARM64.HasFP},
+		//  {"asimd", &ARM64.HasASIMD},
+	}
+
 	// HWCAP feature bits
-	ARM64.HasFP = isSet(arm64_hwcap, _ARM64_FEATURE_HAS_FP)
-	ARM64.HasASIMD = isSet(arm64_hwcap, _ARM64_FEATURE_HAS_ASIMD)
-	ARM64.HasEVTSTRM = isSet(arm64_hwcap, _ARM64_FEATURE_HAS_EVTSTRM)
-	ARM64.HasAES = isSet(arm64_hwcap, _ARM64_FEATURE_HAS_AES)
-	ARM64.HasPMULL = isSet(arm64_hwcap, _ARM64_FEATURE_HAS_PMULL)
-	ARM64.HasSHA1 = isSet(arm64_hwcap, _ARM64_FEATURE_HAS_SHA1)
-	ARM64.HasSHA2 = isSet(arm64_hwcap, _ARM64_FEATURE_HAS_SHA2)
-	ARM64.HasCRC32 = isSet(arm64_hwcap, _ARM64_FEATURE_HAS_CRC32)
-	ARM64.HasATOMICS = isSet(arm64_hwcap, _ARM64_FEATURE_HAS_ATOMICS)
+	ARM64.HasFP = isSet(HWCap, hwcap_FP)
+	ARM64.HasASIMD = isSet(HWCap, hwcap_ASIMD)
+	ARM64.HasEVTSTRM = isSet(HWCap, hwcap_EVTSTRM)
+	ARM64.HasAES = isSet(HWCap, hwcap_AES)
+	ARM64.HasPMULL = isSet(HWCap, hwcap_PMULL)
+	ARM64.HasSHA1 = isSet(HWCap, hwcap_SHA1)
+	ARM64.HasSHA2 = isSet(HWCap, hwcap_SHA2)
+	ARM64.HasCRC32 = isSet(HWCap, hwcap_CRC32)
+	ARM64.HasATOMICS = isSet(HWCap, hwcap_ATOMICS)
+	ARM64.HasFPHP = isSet(HWCap, hwcap_FPHP)
+	ARM64.HasASIMDHP = isSet(HWCap, hwcap_ASIMDHP)
+	ARM64.HasCPUID = isSet(HWCap, hwcap_CPUID)
+	ARM64.HasASIMDRDM = isSet(HWCap, hwcap_ASIMDRDM)
+	ARM64.HasJSCVT = isSet(HWCap, hwcap_JSCVT)
+	ARM64.HasFCMA = isSet(HWCap, hwcap_FCMA)
+	ARM64.HasLRCPC = isSet(HWCap, hwcap_LRCPC)
+	ARM64.HasDCPOP = isSet(HWCap, hwcap_DCPOP)
+	ARM64.HasSHA3 = isSet(HWCap, hwcap_SHA3)
+	ARM64.HasSM3 = isSet(HWCap, hwcap_SM3)
+	ARM64.HasSM4 = isSet(HWCap, hwcap_SM4)
+	ARM64.HasASIMDDP = isSet(HWCap, hwcap_ASIMDDP)
+	ARM64.HasSHA512 = isSet(HWCap, hwcap_SHA512)
+	ARM64.HasSVE = isSet(HWCap, hwcap_SVE)
+	ARM64.HasASIMDFHM = isSet(HWCap, hwcap_ASIMDFHM)
 }
 
 func isSet(hwc uint, value uint) bool {
diff --git a/libgo/go/internal/cpu/cpu_arm64_test.go b/libgo/go/internal/cpu/cpu_arm64_test.go
new file mode 100644
index 0000000..f4c419a
--- /dev/null
+++ b/libgo/go/internal/cpu/cpu_arm64_test.go
@@ -0,0 +1,26 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cpu_test
+
+import (
+	. "internal/cpu"
+	"runtime"
+	"testing"
+)
+
+func TestARM64minimalFeatures(t *testing.T) {
+	switch runtime.GOOS {
+	case "linux", "android":
+	default:
+		t.Skipf("%s/arm64 is not supported", runtime.GOOS)
+	}
+
+	if !ARM64.HasASIMD {
+		t.Fatalf("HasASIMD expected true, got false")
+	}
+	if !ARM64.HasFP {
+		t.Fatalf("HasFP expected true, got false")
+	}
+}
diff --git a/libgo/go/internal/cpu/cpu_gccgo.c b/libgo/go/internal/cpu/cpu_gccgo.c
new file mode 100644
index 0000000..6625ddc
--- /dev/null
+++ b/libgo/go/internal/cpu/cpu_gccgo.c
@@ -0,0 +1,66 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include <stdint.h>
+
+#if defined(__i386__) || defined(__x86_64__)
+#include <cpuid.h>
+#include <x86intrin.h>
+#endif
+
+#include "runtime.h"
+
+#if defined(__i386__) || defined(__x86_64__)
+
+struct cpuid_ret {
+	uint32_t eax;
+	uint32_t ebx;
+	uint32_t ecx;
+	uint32_t edx;
+};
+
+struct cpuid_ret cpuid(uint32_t, uint32_t)
+  __asm__(GOSYM_PREFIX "internal_cpu.cpuid")
+  __attribute__((no_split_stack));
+
+struct cpuid_ret cpuid(uint32_t eaxArg, uint32_t ecxArg) {
+	unsigned int eax = 0;
+	unsigned int ebx = 0;
+	unsigned int ecx = 0;
+	unsigned int edx = 0;
+	struct cpuid_ret ret;
+
+	__get_cpuid_count(eaxArg, ecxArg, &eax, &ebx, &ecx, &edx);
+	ret.eax = (uint32_t)(eax);
+	ret.ebx = (uint32_t)(ebx);
+	ret.ecx = (uint32_t)(ecx);
+	ret.edx = (uint32_t)(edx);
+	return ret;
+}
+
+struct xgetbv_ret {
+	uint32_t eax;
+	uint32_t edx;
+};
+
+struct xgetbv_ret xgetbv(void)
+  __asm__(GOSYM_PREFIX "internal_cpu.xgetbv")
+  __attribute__((no_split_stack));
+
+#pragma GCC push_options
+#pragma GCC target("xsave")
+
+struct xgetbv_ret xgetbv(void) {
+	long long r;
+	struct xgetbv_ret ret;
+
+	r = _xgetbv(0);
+	ret.eax = r & 0xffffffff;
+	ret.edx = r >> 32;
+	return ret;
+}
+
+#pragma GCC pop_options
+
+#endif /* defined(__i386__) || defined(__x86_64__)  */
diff --git a/libgo/go/internal/cpu/cpu_no_init.go b/libgo/go/internal/cpu/cpu_no_init.go
new file mode 100644
index 0000000..1be4f29
--- /dev/null
+++ b/libgo/go/internal/cpu/cpu_no_init.go
@@ -0,0 +1,16 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !386
+// +build !amd64
+// +build !amd64p32
+// +build !arm64
+// +build !ppc64
+// +build !ppc64le
+// +build !s390x
+
+package cpu
+
+func doinit() {
+}
diff --git a/libgo/go/internal/cpu/cpu_ppc64x.go b/libgo/go/internal/cpu/cpu_ppc64x.go
index 7f09372..d3f02ef 100644
--- a/libgo/go/internal/cpu/cpu_ppc64x.go
+++ b/libgo/go/internal/cpu/cpu_ppc64x.go
@@ -9,10 +9,10 @@ package cpu
 const CacheLineSize = 128
 
 // ppc64x doesn't have a 'cpuid' equivalent, so we rely on HWCAP/HWCAP2.
-// These are linknamed in runtime/os_linux_ppc64x.go and are initialized by
-// archauxv().
-var ppc64x_hwcap uint
-var ppc64x_hwcap2 uint
+// These are initialized by archauxv in runtime/os_linux_ppc64x.go.
+// These should not be changed after they are initialized.
+var HWCap uint
+var HWCap2 uint
 
 // HWCAP/HWCAP2 bits. These are exposed by the kernel.
 const (
@@ -32,21 +32,35 @@ const (
 	_PPC_FEATURE2_SCV            = 0x00100000
 )
 
-func init() {
+func doinit() {
+	options = []option{
+		{"htm", &PPC64.HasHTM},
+		{"htmnosc", &PPC64.HasHTMNOSC},
+		{"darn", &PPC64.HasDARN},
+		{"scv", &PPC64.HasSCV},
+
+		// These capabilities should always be enabled on ppc64 and ppc64le:
+		//  {"vmx", &PPC64.HasVMX},
+		//  {"dfp", &PPC64.HasDFP},
+		//  {"vsx", &PPC64.HasVSX},
+		//  {"isel", &PPC64.HasISEL},
+		//  {"vcrypto", &PPC64.HasVCRYPTO},
+	}
+
 	// HWCAP feature bits
-	PPC64.HasVMX = isSet(ppc64x_hwcap, _PPC_FEATURE_HAS_ALTIVEC)
-	PPC64.HasDFP = isSet(ppc64x_hwcap, _PPC_FEATURE_HAS_DFP)
-	PPC64.HasVSX = isSet(ppc64x_hwcap, _PPC_FEATURE_HAS_VSX)
+	PPC64.HasVMX = isSet(HWCap, _PPC_FEATURE_HAS_ALTIVEC)
+	PPC64.HasDFP = isSet(HWCap, _PPC_FEATURE_HAS_DFP)
+	PPC64.HasVSX = isSet(HWCap, _PPC_FEATURE_HAS_VSX)
 
 	// HWCAP2 feature bits
-	PPC64.IsPOWER8 = isSet(ppc64x_hwcap2, _PPC_FEATURE2_ARCH_2_07)
-	PPC64.HasHTM = isSet(ppc64x_hwcap2, _PPC_FEATURE2_HAS_HTM)
-	PPC64.HasISEL = isSet(ppc64x_hwcap2, _PPC_FEATURE2_HAS_ISEL)
-	PPC64.HasVCRYPTO = isSet(ppc64x_hwcap2, _PPC_FEATURE2_HAS_VEC_CRYPTO)
-	PPC64.HasHTMNOSC = isSet(ppc64x_hwcap2, _PPC_FEATURE2_HTM_NOSC)
-	PPC64.IsPOWER9 = isSet(ppc64x_hwcap2, _PPC_FEATURE2_ARCH_3_00)
-	PPC64.HasDARN = isSet(ppc64x_hwcap2, _PPC_FEATURE2_DARN)
-	PPC64.HasSCV = isSet(ppc64x_hwcap2, _PPC_FEATURE2_SCV)
+	PPC64.IsPOWER8 = isSet(HWCap2, _PPC_FEATURE2_ARCH_2_07)
+	PPC64.HasHTM = isSet(HWCap2, _PPC_FEATURE2_HAS_HTM)
+	PPC64.HasISEL = isSet(HWCap2, _PPC_FEATURE2_HAS_ISEL)
+	PPC64.HasVCRYPTO = isSet(HWCap2, _PPC_FEATURE2_HAS_VEC_CRYPTO)
+	PPC64.HasHTMNOSC = isSet(HWCap2, _PPC_FEATURE2_HTM_NOSC)
+	PPC64.IsPOWER9 = isSet(HWCap2, _PPC_FEATURE2_ARCH_3_00)
+	PPC64.HasDARN = isSet(HWCap2, _PPC_FEATURE2_DARN)
+	PPC64.HasSCV = isSet(HWCap2, _PPC_FEATURE2_SCV)
 }
 
 func isSet(hwc uint, value uint) bool {
diff --git a/libgo/go/internal/cpu/cpu_ppc64x_test.go b/libgo/go/internal/cpu/cpu_ppc64x_test.go
new file mode 100644
index 0000000..9c43d1e
--- /dev/null
+++ b/libgo/go/internal/cpu/cpu_ppc64x_test.go
@@ -0,0 +1,33 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ppc64 ppc64le
+
+package cpu_test
+
+import (
+	. "internal/cpu"
+	"testing"
+)
+
+func TestPPC64minimalFeatures(t *testing.T) {
+	if !PPC64.IsPOWER8 {
+		t.Fatalf("IsPOWER8 expected true, got false")
+	}
+	if !PPC64.HasVMX {
+		t.Fatalf("HasVMX expected true, got false")
+	}
+	if !PPC64.HasDFP {
+		t.Fatalf("HasDFP expected true, got false")
+	}
+	if !PPC64.HasVSX {
+		t.Fatalf("HasVSX expected true, got false")
+	}
+	if !PPC64.HasISEL {
+		t.Fatalf("HasISEL expected true, got false")
+	}
+	if !PPC64.HasVCRYPTO {
+		t.Fatalf("HasVCRYPTO expected true, got false")
+	}
+}
diff --git a/libgo/go/internal/cpu/cpu_s390x.go b/libgo/go/internal/cpu/cpu_s390x.go
index 4455809..9dedb4c 100644
--- a/libgo/go/internal/cpu/cpu_s390x.go
+++ b/libgo/go/internal/cpu/cpu_s390x.go
@@ -5,3 +5,149 @@
 package cpu
 
 const CacheLineSize = 256
+
+// bitIsSet reports whether the bit at index is set. The bit index
+// is in big endian order, so bit index 0 is the leftmost bit.
+func bitIsSet(bits []uint64, index uint) bool {
+	return bits[index/64]&((1<<63)>>(index%64)) != 0
+}
+
+// function is the function code for the named function.
+type function uint8
+
+const (
+	// KM{,A,C,CTR} function codes
+	aes128 function = 18 // AES-128
+	aes192          = 19 // AES-192
+	aes256          = 20 // AES-256
+
+	// K{I,L}MD function codes
+	sha1   = 1 // SHA-1
+	sha256 = 2 // SHA-256
+	sha512 = 3 // SHA-512
+
+	// KLMD function codes
+	ghash = 65 // GHASH
+)
+
+// queryResult contains the result of a Query function
+// call. Bits are numbered in big endian order so the
+// leftmost bit (the MSB) is at index 0.
+type queryResult struct {
+	bits [2]uint64
+}
+
+// Has reports whether the given functions are present.
+func (q *queryResult) Has(fns ...function) bool {
+	if len(fns) == 0 {
+		panic("no function codes provided")
+	}
+	for _, f := range fns {
+		if !bitIsSet(q.bits[:], uint(f)) {
+			return false
+		}
+	}
+	return true
+}
+
+// facility is a bit index for the named facility.
+type facility uint8
+
+const (
+	// mandatory facilities
+	zarch  facility = 1  // z architecture mode is active
+	stflef          = 7  // store-facility-list-extended
+	ldisp           = 18 // long-displacement
+	eimm            = 21 // extended-immediate
+
+	// miscellaneous facilities
+	dfp    = 42 // decimal-floating-point
+	etf3eh = 30 // extended-translation 3 enhancement
+
+	// cryptography facilities
+	msa  = 17  // message-security-assist
+	msa3 = 76  // message-security-assist extension 3
+	msa4 = 77  // message-security-assist extension 4
+	msa5 = 57  // message-security-assist extension 5
+	msa8 = 146 // message-security-assist extension 8
+
+	// Note: vx and highgprs are excluded because they require
+	// kernel support and so must be fetched from HWCAP.
+)
+
+// facilityList contains the result of an STFLE call.
+// Bits are numbered in big endian order so the
+// leftmost bit (the MSB) is at index 0.
+type facilityList struct {
+	bits [4]uint64
+}
+
+// Has reports whether the given facilities are present.
+func (s *facilityList) Has(fs ...facility) bool {
+	if len(fs) == 0 {
+		panic("no facility bits provided")
+	}
+	for _, f := range fs {
+		if !bitIsSet(s.bits[:], uint(f)) {
+			return false
+		}
+	}
+	return true
+}
+
+// The following feature detection functions are defined in cpu_s390x.s.
+// They are likely to be expensive to call so the results should be cached.
+func stfle() facilityList     { panic("not implemented for gccgo") }
+func kmQuery() queryResult    { panic("not implemented for gccgo") }
+func kmcQuery() queryResult   { panic("not implemented for gccgo") }
+func kmctrQuery() queryResult { panic("not implemented for gccgo") }
+func kmaQuery() queryResult   { panic("not implemented for gccgo") }
+func kimdQuery() queryResult  { panic("not implemented for gccgo") }
+func klmdQuery() queryResult  { panic("not implemented for gccgo") }
+
+func doinit() {
+	options = []option{
+		{"zarch", &S390X.HasZArch},
+		{"stfle", &S390X.HasSTFLE},
+		{"ldisp", &S390X.HasLDisp},
+		{"msa", &S390X.HasMSA},
+		{"eimm", &S390X.HasEImm},
+		{"dfp", &S390X.HasDFP},
+		{"etf3eh", &S390X.HasETF3Enhanced},
+		{"vx", &S390X.HasVX},
+	}
+
+	aes := []function{aes128, aes192, aes256}
+	facilities := stfle()
+
+	S390X.HasZArch = facilities.Has(zarch)
+	S390X.HasSTFLE = facilities.Has(stflef)
+	S390X.HasLDisp = facilities.Has(ldisp)
+	S390X.HasEImm = facilities.Has(eimm)
+	S390X.HasDFP = facilities.Has(dfp)
+	S390X.HasETF3Enhanced = facilities.Has(etf3eh)
+	S390X.HasMSA = facilities.Has(msa)
+
+	if S390X.HasMSA {
+		// cipher message
+		km, kmc := kmQuery(), kmcQuery()
+		S390X.HasAES = km.Has(aes...)
+		S390X.HasAESCBC = kmc.Has(aes...)
+		if facilities.Has(msa4) {
+			kmctr := kmctrQuery()
+			S390X.HasAESCTR = kmctr.Has(aes...)
+		}
+		if facilities.Has(msa8) {
+			kma := kmaQuery()
+			S390X.HasAESGCM = kma.Has(aes...)
+		}
+
+		// compute message digest
+		kimd := kimdQuery() // intermediate (no padding)
+		klmd := klmdQuery() // last (padding)
+		S390X.HasSHA1 = kimd.Has(sha1) && klmd.Has(sha1)
+		S390X.HasSHA256 = kimd.Has(sha256) && klmd.Has(sha256)
+		S390X.HasSHA512 = kimd.Has(sha512) && klmd.Has(sha512)
+		S390X.HasGHASH = kimd.Has(ghash) // KLMD-GHASH does not exist
+	}
+}
diff --git a/libgo/go/internal/cpu/cpu_s390x_test.go b/libgo/go/internal/cpu/cpu_s390x_test.go
new file mode 100644
index 0000000..d910bbe
--- /dev/null
+++ b/libgo/go/internal/cpu/cpu_s390x_test.go
@@ -0,0 +1,63 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cpu_test
+
+import (
+	"errors"
+	. "internal/cpu"
+	"io/ioutil"
+	"regexp"
+	"testing"
+)
+
+func getFeatureList() ([]string, error) {
+	cpuinfo, err := ioutil.ReadFile("/proc/cpuinfo")
+	if err != nil {
+		return nil, err
+	}
+	r := regexp.MustCompile("features\\s*:\\s*(.*)")
+	b := r.FindSubmatch(cpuinfo)
+	if len(b) < 2 {
+		return nil, errors.New("no feature list in /proc/cpuinfo")
+	}
+	return regexp.MustCompile("\\s+").Split(string(b[1]), -1), nil
+}
+
+func TestS390XAgainstCPUInfo(t *testing.T) {
+	// mapping of linux feature strings to S390X fields
+	mapping := make(map[string]*bool)
+	for _, option := range Options {
+		mapping[option.Name] = option.Feature
+	}
+
+	// these must be true on the machines Go supports
+	mandatory := make(map[string]bool)
+	mandatory["zarch"] = false
+	mandatory["eimm"] = false
+	mandatory["ldisp"] = false
+	mandatory["stfle"] = false
+
+	features, err := getFeatureList()
+	if err != nil {
+		t.Error(err)
+	}
+	for _, feature := range features {
+		if _, ok := mandatory[feature]; ok {
+			mandatory[feature] = true
+		}
+		if flag, ok := mapping[feature]; ok {
+			if !*flag {
+				t.Errorf("feature '%v' not detected", feature)
+			}
+		} else {
+			t.Logf("no entry for '%v'", feature)
+		}
+	}
+	for k, v := range mandatory {
+		if !v {
+			t.Errorf("mandatory feature '%v' not detected", k)
+		}
+	}
+}
diff --git a/libgo/go/internal/cpu/cpu_test.go b/libgo/go/internal/cpu/cpu_test.go
index 07b0243..d4115a1 100644
--- a/libgo/go/internal/cpu/cpu_test.go
+++ b/libgo/go/internal/cpu/cpu_test.go
@@ -5,46 +5,52 @@
 package cpu_test
 
 import (
-	"internal/cpu"
-	"runtime"
+	. "internal/cpu"
+	"internal/testenv"
+	"os"
+	"os/exec"
+	"strings"
 	"testing"
 )
 
-func TestAMD64minimalFeatures(t *testing.T) {
-	if runtime.GOARCH == "amd64" {
-		if !cpu.X86.HasSSE2 {
-			t.Fatalf("HasSSE2 expected true, got false")
-		}
+func MustHaveDebugOptionsEnabled(t *testing.T) {
+	if !DebugOptions {
+		t.Skipf("skipping test: cpu feature options not enabled")
 	}
 }
 
-func TestAVX2hasAVX(t *testing.T) {
-	if runtime.GOARCH == "amd64" {
-		if cpu.X86.HasAVX2 && !cpu.X86.HasAVX {
-			t.Fatalf("HasAVX expected true, got false")
-		}
+func runDebugOptionsTest(t *testing.T, test string, options string) {
+	MustHaveDebugOptionsEnabled(t)
+
+	testenv.MustHaveExec(t)
+
+	env := "GODEBUGCPU=" + options
+
+	cmd := exec.Command(os.Args[0], "-test.run="+test)
+	cmd.Env = append(cmd.Env, env)
+
+	output, err := cmd.CombinedOutput()
+	got := strings.TrimSpace(string(output))
+	want := "PASS"
+	if err != nil || got != want {
+		t.Fatalf("%s with %s: want %s, got %v", test, env, want, got)
 	}
 }
 
-func TestPPC64minimalFeatures(t *testing.T) {
-	if runtime.GOARCH == "ppc64" || runtime.GOARCH == "ppc64le" {
-		if !cpu.PPC64.IsPOWER8 {
-			t.Fatalf("IsPOWER8 expected true, got false")
-		}
-		if !cpu.PPC64.HasVMX {
-			t.Fatalf("HasVMX expected true, got false")
-		}
-		if !cpu.PPC64.HasDFP {
-			t.Fatalf("HasDFP expected true, got false")
-		}
-		if !cpu.PPC64.HasVSX {
-			t.Fatalf("HasVSX expected true, got false")
-		}
-		if !cpu.PPC64.HasISEL {
-			t.Fatalf("HasISEL expected true, got false")
-		}
-		if !cpu.PPC64.HasVCRYPTO {
-			t.Fatalf("HasVCRYPTO expected true, got false")
+func TestDisableAllCapabilities(t *testing.T) {
+	runDebugOptionsTest(t, "TestAllCapabilitiesDisabled", "all=0")
+}
+
+func TestAllCapabilitiesDisabled(t *testing.T) {
+	MustHaveDebugOptionsEnabled(t)
+
+	if os.Getenv("GODEBUGCPU") != "all=0" {
+		t.Skipf("skipping test: GODEBUGCPU=all=0 not set")
+	}
+
+	for _, o := range Options {
+		if got := *o.Feature; got != false {
+			t.Errorf("%v: expected false, got %v", o.Name, got)
 		}
 	}
 }
diff --git a/libgo/go/internal/cpu/cpu_wasm.go b/libgo/go/internal/cpu/cpu_wasm.go
new file mode 100644
index 0000000..1107a7a
--- /dev/null
+++ b/libgo/go/internal/cpu/cpu_wasm.go
@@ -0,0 +1,7 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cpu
+
+const CacheLineSize = 64
diff --git a/libgo/go/internal/cpu/cpu_x86.go b/libgo/go/internal/cpu/cpu_x86.go
index 34c632f..7d9d3aa 100644
--- a/libgo/go/internal/cpu/cpu_x86.go
+++ b/libgo/go/internal/cpu/cpu_x86.go
@@ -14,7 +14,56 @@ func cpuid(eaxArg, ecxArg uint32) (eax, ebx, ecx, edx uint32)
 // xgetbv with ecx = 0 is implemented in cpu_x86.s.
 func xgetbv() (eax, edx uint32)
 
-func init() {
+const (
+	// edx bits
+	cpuid_SSE2 = 1 << 26
+
+	// ecx bits
+	cpuid_SSE3      = 1 << 0
+	cpuid_PCLMULQDQ = 1 << 1
+	cpuid_SSSE3     = 1 << 9
+	cpuid_FMA       = 1 << 12
+	cpuid_SSE41     = 1 << 19
+	cpuid_SSE42     = 1 << 20
+	cpuid_POPCNT    = 1 << 23
+	cpuid_AES       = 1 << 25
+	cpuid_OSXSAVE   = 1 << 27
+	cpuid_AVX       = 1 << 28
+
+	// ebx bits
+	cpuid_BMI1 = 1 << 3
+	cpuid_AVX2 = 1 << 5
+	cpuid_BMI2 = 1 << 8
+	cpuid_ERMS = 1 << 9
+	cpuid_ADX  = 1 << 19
+)
+
+func doinit() {
+	options = []option{
+		{"adx", &X86.HasADX},
+		{"aes", &X86.HasAES},
+		{"avx", &X86.HasAVX},
+		{"avx2", &X86.HasAVX2},
+		{"bmi1", &X86.HasBMI1},
+		{"bmi2", &X86.HasBMI2},
+		{"erms", &X86.HasERMS},
+		{"fma", &X86.HasFMA},
+		{"pclmulqdq", &X86.HasPCLMULQDQ},
+		{"popcnt", &X86.HasPOPCNT},
+		{"sse3", &X86.HasSSE3},
+		{"sse41", &X86.HasSSE41},
+		{"sse42", &X86.HasSSE42},
+		{"ssse3", &X86.HasSSSE3},
+
+		// sse2 set as last element so it can easily be removed again. See code below.
+		{"sse2", &X86.HasSSE2},
+	}
+
+	// Remove sse2 from options on amd64(p32) because SSE2 is a mandatory feature for these GOARCHs.
+	if GOARCH == "amd64" || GOARCH == "amd64p32" {
+		options = options[:len(options)-1]
+	}
+
 	maxID, _, _, _ := cpuid(0, 0)
 
 	if maxID < 1 {
@@ -22,40 +71,40 @@ func init() {
 	}
 
 	_, _, ecx1, edx1 := cpuid(1, 0)
-	X86.HasSSE2 = isSet(26, edx1)
-
-	X86.HasSSE3 = isSet(0, ecx1)
-	X86.HasPCLMULQDQ = isSet(1, ecx1)
-	X86.HasSSSE3 = isSet(9, ecx1)
-	X86.HasFMA = isSet(12, ecx1)
-	X86.HasSSE41 = isSet(19, ecx1)
-	X86.HasSSE42 = isSet(20, ecx1)
-	X86.HasPOPCNT = isSet(23, ecx1)
-	X86.HasAES = isSet(25, ecx1)
-	X86.HasOSXSAVE = isSet(27, ecx1)
+	X86.HasSSE2 = isSet(edx1, cpuid_SSE2)
+
+	X86.HasSSE3 = isSet(ecx1, cpuid_SSE3)
+	X86.HasPCLMULQDQ = isSet(ecx1, cpuid_PCLMULQDQ)
+	X86.HasSSSE3 = isSet(ecx1, cpuid_SSSE3)
+	X86.HasFMA = isSet(ecx1, cpuid_FMA)
+	X86.HasSSE41 = isSet(ecx1, cpuid_SSE41)
+	X86.HasSSE42 = isSet(ecx1, cpuid_SSE42)
+	X86.HasPOPCNT = isSet(ecx1, cpuid_POPCNT)
+	X86.HasAES = isSet(ecx1, cpuid_AES)
+	X86.HasOSXSAVE = isSet(ecx1, cpuid_OSXSAVE)
 
 	osSupportsAVX := false
 	// For XGETBV, OSXSAVE bit is required and sufficient.
 	if X86.HasOSXSAVE {
 		eax, _ := xgetbv()
 		// Check if XMM and YMM registers have OS support.
-		osSupportsAVX = isSet(1, eax) && isSet(2, eax)
+		osSupportsAVX = isSet(eax, 1<<1) && isSet(eax, 1<<2)
 	}
 
-	X86.HasAVX = isSet(28, ecx1) && osSupportsAVX
+	X86.HasAVX = isSet(ecx1, cpuid_AVX) && osSupportsAVX
 
 	if maxID < 7 {
 		return
 	}
 
 	_, ebx7, _, _ := cpuid(7, 0)
-	X86.HasBMI1 = isSet(3, ebx7)
-	X86.HasAVX2 = isSet(5, ebx7) && osSupportsAVX
-	X86.HasBMI2 = isSet(8, ebx7)
-	X86.HasERMS = isSet(9, ebx7)
-	X86.HasADX = isSet(19, ebx7)
+	X86.HasBMI1 = isSet(ebx7, cpuid_BMI1)
+	X86.HasAVX2 = isSet(ebx7, cpuid_AVX2) && osSupportsAVX
+	X86.HasBMI2 = isSet(ebx7, cpuid_BMI2)
+	X86.HasERMS = isSet(ebx7, cpuid_ERMS)
+	X86.HasADX = isSet(ebx7, cpuid_ADX)
 }
 
-func isSet(bitpos uint, value uint32) bool {
-	return value&(1<<bitpos) != 0
+func isSet(hwc uint32, value uint32) bool {
+	return hwc&value != 0
 }
diff --git a/libgo/go/internal/cpu/cpu_x86_test.go b/libgo/go/internal/cpu/cpu_x86_test.go
new file mode 100644
index 0000000..d03306c
--- /dev/null
+++ b/libgo/go/internal/cpu/cpu_x86_test.go
@@ -0,0 +1,47 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build 386 amd64 amd64p32
+
+package cpu_test
+
+import (
+	. "internal/cpu"
+	"os"
+	"runtime"
+	"testing"
+)
+
+func TestAMD64minimalFeatures(t *testing.T) {
+	if runtime.GOARCH != "amd64" {
+		return
+	}
+
+	if !X86.HasSSE2 {
+		t.Fatalf("HasSSE2 expected true, got false")
+	}
+}
+
+func TestX86ifAVX2hasAVX(t *testing.T) {
+	if X86.HasAVX2 && !X86.HasAVX {
+		t.Fatalf("HasAVX expected true when HasAVX2 is true, got false")
+	}
+}
+
+func TestDisableSSE2(t *testing.T) {
+	runDebugOptionsTest(t, "TestSSE2DebugOption", "sse2=0")
+}
+
+func TestSSE2DebugOption(t *testing.T) {
+	MustHaveDebugOptionsEnabled(t)
+
+	if os.Getenv("GODEBUGCPU") != "sse2=0" {
+		t.Skipf("skipping test: GODEBUGCPU=sse2=0 not set")
+	}
+
+	want := runtime.GOARCH != "386" // SSE2 can only be disabled on 386.
+	if got := X86.HasSSE2; got != want {
+		t.Errorf("X86.HasSSE2 on %s expected %v, got %v", runtime.GOARCH, want, got)
+	}
+}
diff --git a/libgo/go/internal/cpu/export_test.go b/libgo/go/internal/cpu/export_test.go
new file mode 100644
index 0000000..91bfc1b
--- /dev/null
+++ b/libgo/go/internal/cpu/export_test.go
@@ -0,0 +1,9 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cpu
+
+var (
+	Options = options
+)
diff --git a/libgo/go/internal/goroot/gc.go b/libgo/go/internal/goroot/gc.go
new file mode 100644
index 0000000..ce4c1e5
--- /dev/null
+++ b/libgo/go/internal/goroot/gc.go
@@ -0,0 +1,141 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build gc
+
+package goroot
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"sync"
+)
+
+// IsStandardPackage returns whether path is a standard package,
+// given goroot and compiler.
+func IsStandardPackage(goroot, compiler, path string) bool {
+	switch compiler {
+	case "gc":
+		dir := filepath.Join(goroot, "src", path)
+		_, err := os.Stat(dir)
+		return err == nil
+	case "gccgo":
+		return gccgoSearch.isStandard(path)
+	default:
+		panic("unknown compiler " + compiler)
+	}
+}
+
+// gccgoSearch holds the gccgo search directories.
+type gccgoDirs struct {
+	once sync.Once
+	dirs []string
+}
+
+// gccgoSearch is used to check whether a gccgo package exists in the
+// standard library.
+var gccgoSearch gccgoDirs
+
+// init finds the gccgo search directories. If this fails it leaves dirs == nil.
+func (gd *gccgoDirs) init() {
+	gccgo := os.Getenv("GCCGO")
+	if gccgo == "" {
+		gccgo = "gccgo"
+	}
+	bin, err := exec.LookPath(gccgo)
+	if err != nil {
+		return
+	}
+
+	allDirs, err := exec.Command(bin, "-print-search-dirs").Output()
+	if err != nil {
+		return
+	}
+	versionB, err := exec.Command(bin, "-dumpversion").Output()
+	if err != nil {
+		return
+	}
+	version := strings.TrimSpace(string(versionB))
+	machineB, err := exec.Command(bin, "-dumpmachine").Output()
+	if err != nil {
+		return
+	}
+	machine := strings.TrimSpace(string(machineB))
+
+	dirsEntries := strings.Split(string(allDirs), "\n")
+	const prefix = "libraries: ="
+	var dirs []string
+	for _, dirEntry := range dirsEntries {
+		if strings.HasPrefix(dirEntry, prefix) {
+			dirs = filepath.SplitList(strings.TrimPrefix(dirEntry, prefix))
+			break
+		}
+	}
+	if len(dirs) == 0 {
+		return
+	}
+
+	var lastDirs []string
+	for _, dir := range dirs {
+		goDir := filepath.Join(dir, "go", version)
+		if fi, err := os.Stat(goDir); err == nil && fi.IsDir() {
+			gd.dirs = append(gd.dirs, goDir)
+			goDir = filepath.Join(goDir, machine)
+			if fi, err = os.Stat(goDir); err == nil && fi.IsDir() {
+				gd.dirs = append(gd.dirs, goDir)
+			}
+		}
+		if fi, err := os.Stat(dir); err == nil && fi.IsDir() {
+			lastDirs = append(lastDirs, dir)
+		}
+	}
+	gd.dirs = append(gd.dirs, lastDirs...)
+}
+
+// isStandard returns whether path is a standard library for gccgo.
+func (gd *gccgoDirs) isStandard(path string) bool {
+	// Quick check: if the first path component has a '.', it's not
+	// in the standard library. This skips most GOPATH directories.
+	i := strings.Index(path, "/")
+	if i < 0 {
+		i = len(path)
+	}
+	if strings.Contains(path[:i], ".") {
+		return false
+	}
+
+	if path == "unsafe" {
+		// Special case.
+		return true
+	}
+
+	gd.once.Do(gd.init)
+	if gd.dirs == nil {
+		// We couldn't find the gccgo search directories.
+		// Best guess, since the first component did not contain
+		// '.', is that this is a standard library package.
+		return true
+	}
+
+	for _, dir := range gd.dirs {
+		full := filepath.Join(dir, path)
+		pkgdir, pkg := filepath.Split(full)
+		for _, p := range [...]string{
+			full,
+			full + ".gox",
+			pkgdir + "lib" + pkg + ".so",
+			pkgdir + "lib" + pkg + ".a",
+			full + ".o",
+		} {
+			if fi, err := os.Stat(p); err == nil && !fi.IsDir() {
+				return true
+			}
+		}
+	}
+
+	return false
+}
diff --git a/libgo/go/internal/goroot/gccgo.go b/libgo/go/internal/goroot/gccgo.go
new file mode 100644
index 0000000..098e77d
--- /dev/null
+++ b/libgo/go/internal/goroot/gccgo.go
@@ -0,0 +1,27 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build gccgo
+
+package goroot
+
+import (
+	"os"
+	"path/filepath"
+)
+
+// IsStandardPackage returns whether path is a standard package,
+// given goroot and compiler.
+func IsStandardPackage(goroot, compiler, path string) bool {
+	switch compiler {
+	case "gc":
+		dir := filepath.Join(goroot, "src", path)
+		_, err := os.Stat(dir)
+		return err == nil
+	case "gccgo":
+		return stdpkg[path]
+	default:
+		panic("unknown compiler " + compiler)
+	}
+}
diff --git a/libgo/go/internal/poll/fd_mutex.go b/libgo/go/internal/poll/fd_mutex.go
index 2ba7de7..0a8ee6f 100644
--- a/libgo/go/internal/poll/fd_mutex.go
+++ b/libgo/go/internal/poll/fd_mutex.go
@@ -34,6 +34,8 @@ const (
 	mutexWMask   = (1<<20 - 1) << 43
 )
 
+const overflowMsg = "too many concurrent operations on a single file or socket (max 1048575)"
+
 // Read operations must do rwlock(true)/rwunlock(true).
 //
 // Write operations must do rwlock(false)/rwunlock(false).
@@ -56,7 +58,7 @@ func (mu *fdMutex) incref() bool {
 		}
 		new := old + mutexRef
 		if new&mutexRefMask == 0 {
-			panic("inconsistent poll.fdMutex")
+			panic(overflowMsg)
 		}
 		if atomic.CompareAndSwapUint64(&mu.state, old, new) {
 			return true
@@ -75,7 +77,7 @@ func (mu *fdMutex) increfAndClose() bool {
 		// Mark as closed and acquire a reference.
 		new := (old | mutexClosed) + mutexRef
 		if new&mutexRefMask == 0 {
-			panic("inconsistent poll.fdMutex")
+			panic(overflowMsg)
 		}
 		// Remove all read and write waiters.
 		new &^= mutexRMask | mutexWMask
@@ -136,13 +138,13 @@ func (mu *fdMutex) rwlock(read bool) bool {
 			// Lock is free, acquire it.
 			new = (old | mutexBit) + mutexRef
 			if new&mutexRefMask == 0 {
-				panic("inconsistent poll.fdMutex")
+				panic(overflowMsg)
 			}
 		} else {
 			// Wait for lock.
 			new = old + mutexWait
 			if new&mutexMask == 0 {
-				panic("inconsistent poll.fdMutex")
+				panic(overflowMsg)
 			}
 		}
 		if atomic.CompareAndSwapUint64(&mu.state, old, new) {
diff --git a/libgo/go/internal/poll/fd_mutex_test.go b/libgo/go/internal/poll/fd_mutex_test.go
index bab81c6..2c53c45 100644
--- a/libgo/go/internal/poll/fd_mutex_test.go
+++ b/libgo/go/internal/poll/fd_mutex_test.go
@@ -8,6 +8,7 @@ import (
 	. "internal/poll"
 	"math/rand"
 	"runtime"
+	"strings"
 	"testing"
 	"time"
 )
@@ -121,6 +122,27 @@ func TestMutexPanic(t *testing.T) {
 	mu.RWUnlock(false)
 }
 
+func TestMutexOverflowPanic(t *testing.T) {
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.Fatal("did not panic")
+		}
+		msg, ok := r.(string)
+		if !ok {
+			t.Fatalf("unexpected panic type %T", r)
+		}
+		if !strings.Contains(msg, "too many") || strings.Contains(msg, "inconsistent") {
+			t.Fatalf("wrong panic message %q", msg)
+		}
+	}()
+
+	var mu1 FDMutex
+	for i := 0; i < 1<<21; i++ {
+		mu1.Incref()
+	}
+}
+
 func TestMutexStress(t *testing.T) {
 	P := 8
 	N := int(1e6)
diff --git a/libgo/go/internal/poll/fd_poll_nacl.go b/libgo/go/internal/poll/fd_poll_nacljs.go
index 2df3003..832dddb 100644
--- a/libgo/go/internal/poll/fd_poll_nacl.go
+++ b/libgo/go/internal/poll/fd_poll_nacljs.go
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build nacl js,wasm
+
 package poll
 
 import (
@@ -40,6 +42,9 @@ func (pd *pollDesc) wait(mode int, isFile bool) error {
 	if pd.closing {
 		return errClosing(isFile)
 	}
+	if isFile { // TODO(neelance): wasm: Use callbacks from JS to block until the read/write finished.
+		return nil
+	}
 	return ErrTimeout
 }
 
diff --git a/libgo/go/internal/poll/fd_posix.go b/libgo/go/internal/poll/fd_posix.go
index 4e6e355..23ad7a0 100644
--- a/libgo/go/internal/poll/fd_posix.go
+++ b/libgo/go/internal/poll/fd_posix.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build aix darwin dragonfly freebsd linux nacl netbsd openbsd solaris windows
+// +build aix darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris windows
 
 package poll
 
diff --git a/libgo/go/internal/poll/fd_unix.go b/libgo/go/internal/poll/fd_unix.go
index cfd441e..28bc32f 100644
--- a/libgo/go/internal/poll/fd_unix.go
+++ b/libgo/go/internal/poll/fd_unix.go
@@ -2,13 +2,14 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build aix darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris
 
 package poll
 
 import (
 	"io"
 	"runtime"
+	"sync/atomic"
 	"syscall"
 )
 
@@ -30,6 +31,9 @@ type FD struct {
 	// Semaphore signaled when file is closed.
 	csema uint32
 
+	// Non-zero if this file has been set to blocking mode.
+	isBlocking uint32
+
 	// Whether this is a streaming descriptor, as opposed to a
 	// packet-based descriptor like a UDP socket. Immutable.
 	IsStream bool
@@ -40,9 +44,6 @@ type FD struct {
 
 	// Whether this is a file rather than a network socket.
 	isFile bool
-
-	// Whether this file has been set to blocking mode.
-	isBlocking bool
 }
 
 // Init initializes the FD. The Sysfd field should already be set.
@@ -56,10 +57,16 @@ func (fd *FD) Init(net string, pollable bool) error {
 		fd.isFile = true
 	}
 	if !pollable {
-		fd.isBlocking = true
+		fd.isBlocking = 1
 		return nil
 	}
-	return fd.pd.init(fd)
+	err := fd.pd.init(fd)
+	if err != nil {
+		// If we could not initialize the runtime poller,
+		// assume we are using blocking mode.
+		fd.isBlocking = 1
+	}
+	return err
 }
 
 // Destroy closes the file descriptor. This is called when there are
@@ -96,7 +103,9 @@ func (fd *FD) Close() error {
 	// reference, it is already closed. Only wait if the file has
 	// not been set to blocking mode, as otherwise any current I/O
 	// may be blocking, and that would block the Close.
-	if !fd.isBlocking {
+	// No need for an atomic read of isBlocking, increfAndClose means
+	// we have exclusive access to fd.
+	if fd.isBlocking == 0 {
 		runtime_Semacquire(&fd.csema)
 	}
 
@@ -118,7 +127,10 @@ func (fd *FD) SetBlocking() error {
 		return err
 	}
 	defer fd.decref()
-	fd.isBlocking = true
+	// Atomic store so that concurrent calls to SetBlocking
+	// do not cause a race condition. isBlocking only ever goes
+	// from 0 to 1 so there is no real race here.
+	atomic.StoreUint32(&fd.isBlocking, 1)
 	return syscall.SetNonblock(fd.Sysfd, false)
 }
 
@@ -433,6 +445,59 @@ func (fd *FD) Fstat(s *syscall.Stat_t) error {
 	return syscall.Fstat(fd.Sysfd, s)
 }
 
+// Use a helper function to call fcntl.  This is defined in C in
+// libgo/runtime.
+//extern __go_fcntl_uintptr
+func fcntl(uintptr, uintptr, uintptr) (uintptr, uintptr)
+
+// tryDupCloexec indicates whether F_DUPFD_CLOEXEC should be used.
+// If the kernel doesn't support it, this is set to 0.
+var tryDupCloexec = int32(1)
+
+// DupCloseOnExec dups fd and marks it close-on-exec.
+func DupCloseOnExec(fd int) (int, string, error) {
+	if atomic.LoadInt32(&tryDupCloexec) == 1 {
+		syscall.Entersyscall()
+		r0, errno := fcntl(uintptr(fd), syscall.F_DUPFD_CLOEXEC, 0)
+		syscall.Exitsyscall()
+		e1 := syscall.Errno(errno)
+		switch e1 {
+		case 0:
+			return int(r0), "", nil
+		case syscall.EINVAL, syscall.ENOSYS:
+			// Old kernel, or js/wasm (which returns
+			// ENOSYS). Fall back to the portable way from
+			// now on.
+			atomic.StoreInt32(&tryDupCloexec, 0)
+		default:
+			return -1, "fcntl", e1
+		}
+	}
+	return dupCloseOnExecOld(fd)
+}
+
+// dupCloseOnExecUnixOld is the traditional way to dup an fd and
+// set its O_CLOEXEC bit, using two system calls.
+func dupCloseOnExecOld(fd int) (int, string, error) {
+	syscall.ForkLock.RLock()
+	defer syscall.ForkLock.RUnlock()
+	newfd, err := syscall.Dup(fd)
+	if err != nil {
+		return -1, "dup", err
+	}
+	syscall.CloseOnExec(newfd)
+	return newfd, "", nil
+}
+
+// Dup duplicates the file descriptor.
+func (fd *FD) Dup() (int, string, error) {
+	if err := fd.incref(); err != nil {
+		return -1, "", err
+	}
+	defer fd.decref()
+	return DupCloseOnExec(fd.Sysfd)
+}
+
 // On Unix variants only, expose the IO event for the net code.
 
 // WaitWrite waits until data can be read from fd.
diff --git a/libgo/go/internal/poll/fd_windows.go b/libgo/go/internal/poll/fd_windows.go
index 187908b..d04d332 100644
--- a/libgo/go/internal/poll/fd_windows.go
+++ b/libgo/go/internal/poll/fd_windows.go
@@ -34,19 +34,18 @@ var (
 
 var canCancelIO bool // determines if CancelIoEx API is present
 
-// This package uses SetFileCompletionNotificationModes Windows API
-// to skip calling GetQueuedCompletionStatus if an IO operation completes
-// synchronously. Unfortuently SetFileCompletionNotificationModes is not
-// available on Windows XP. Also there is a known bug where
-// SetFileCompletionNotificationModes crashes on some systems
-// (see http://support.microsoft.com/kb/2568167 for details).
+// This package uses the SetFileCompletionNotificationModes Windows
+// API to skip calling GetQueuedCompletionStatus if an IO operation
+// completes synchronously. There is a known bug where
+// SetFileCompletionNotificationModes crashes on some systems (see
+// https://support.microsoft.com/kb/2568167 for details).
 
 var useSetFileCompletionNotificationModes bool // determines is SetFileCompletionNotificationModes is present and safe to use
 
 // checkSetFileCompletionNotificationModes verifies that
 // SetFileCompletionNotificationModes Windows API is present
 // on the system and is safe to use.
-// See http://support.microsoft.com/kb/2568167 for details.
+// See https://support.microsoft.com/kb/2568167 for details.
 func checkSetFileCompletionNotificationModes() {
 	err := syscall.LoadSetFileCompletionNotificationModes()
 	if err != nil {
@@ -225,6 +224,10 @@ func (s *ioSrv) ExecIO(o *operation, submit func(o *operation) error) (int, erro
 		// All is good. Extract our IO results and return.
 		if o.errno != 0 {
 			err = syscall.Errno(o.errno)
+			// More data available. Return back the size of received data.
+			if err == syscall.ERROR_MORE_DATA || err == windows.WSAEMSGSIZE {
+				return int(o.qty), err
+			}
 			return 0, err
 		}
 		return int(o.qty), nil
@@ -379,7 +382,7 @@ func (fd *FD) Init(net string, pollable bool) (string, error) {
 		// We do not use events, so we can skip them always.
 		flags := uint8(syscall.FILE_SKIP_SET_EVENT_ON_HANDLE)
 		// It's not safe to skip completion notifications for UDP:
-		// http://blogs.technet.com/b/winserverperformance/archive/2008/06/26/designing-applications-for-high-performance-part-iii.aspx
+		// https://blogs.technet.com/b/winserverperformance/archive/2008/06/26/designing-applications-for-high-performance-part-iii.aspx
 		if net == "tcp" {
 			flags |= syscall.FILE_SKIP_COMPLETION_PORT_ON_SUCCESS
 		}
@@ -909,12 +912,46 @@ func (fd *FD) RawControl(f func(uintptr)) error {
 
 // RawRead invokes the user-defined function f for a read operation.
 func (fd *FD) RawRead(f func(uintptr) bool) error {
-	return errors.New("not implemented")
+	if err := fd.readLock(); err != nil {
+		return err
+	}
+	defer fd.readUnlock()
+	for {
+		if f(uintptr(fd.Sysfd)) {
+			return nil
+		}
+
+		// Use a zero-byte read as a way to get notified when this
+		// socket is readable. h/t https://stackoverflow.com/a/42019668/332798
+		o := &fd.rop
+		o.InitBuf(nil)
+		if !fd.IsStream {
+			o.flags |= windows.MSG_PEEK
+		}
+		_, err := rsrv.ExecIO(o, func(o *operation) error {
+			return syscall.WSARecv(o.fd.Sysfd, &o.buf, 1, &o.qty, &o.flags, &o.o, nil)
+		})
+		if err == windows.WSAEMSGSIZE {
+			// expected with a 0-byte peek, ignore.
+		} else if err != nil {
+			return err
+		}
+	}
 }
 
 // RawWrite invokes the user-defined function f for a write operation.
 func (fd *FD) RawWrite(f func(uintptr) bool) error {
-	return errors.New("not implemented")
+	if err := fd.writeLock(); err != nil {
+		return err
+	}
+	defer fd.writeUnlock()
+
+	if f(uintptr(fd.Sysfd)) {
+		return nil
+	}
+
+	// TODO(tmm1): find a way to detect socket writability
+	return syscall.EWINDOWS
 }
 
 func sockaddrToRaw(sa syscall.Sockaddr) (unsafe.Pointer, int32, error) {
diff --git a/libgo/go/internal/poll/hook_cloexec.go b/libgo/go/internal/poll/hook_cloexec.go
index 73df6ed..5c93bda 100644
--- a/libgo/go/internal/poll/hook_cloexec.go
+++ b/libgo/go/internal/poll/hook_cloexec.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build dragonfly freebsd linux
+// +build dragonfly freebsd linux netbsd openbsd
 
 package poll
 
diff --git a/libgo/go/internal/poll/hook_unix.go b/libgo/go/internal/poll/hook_unix.go
index 4cf36cc..a7512b1 100644
--- a/libgo/go/internal/poll/hook_unix.go
+++ b/libgo/go/internal/poll/hook_unix.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build aix darwin dragonfly freebsd linux nacl netbsd openbsd solaris
+// +build aix darwin dragonfly freebsd js,wasm linux nacl netbsd openbsd solaris
 
 package poll
 
diff --git a/libgo/go/internal/poll/sendfile_windows.go b/libgo/go/internal/poll/sendfile_windows.go
index 4a15b75..dc93e85 100644
--- a/libgo/go/internal/poll/sendfile_windows.go
+++ b/libgo/go/internal/poll/sendfile_windows.go
@@ -25,6 +25,16 @@ func SendFile(fd *FD, src syscall.Handle, n int64) (int64, error) {
 	o := &fd.wop
 	o.qty = uint32(n)
 	o.handle = src
+
+	// TODO(brainman): skip calling syscall.Seek if OS allows it
+	curpos, err := syscall.Seek(o.handle, 0, 1)
+	if err != nil {
+		return 0, err
+	}
+
+	o.o.Offset = uint32(curpos)
+	o.o.OffsetHigh = uint32(curpos >> 32)
+
 	done, err := wsrv.ExecIO(o, func(o *operation) error {
 		return syscall.TransmitFile(o.fd.Sysfd, o.handle, o.qty, 0, &o.o, nil, syscall.TF_WRITE_BEHIND)
 	})
diff --git a/libgo/go/internal/poll/sock_cloexec.go b/libgo/go/internal/poll/sock_cloexec.go
index 0d5c8bd..691cb8e 100644
--- a/libgo/go/internal/poll/sock_cloexec.go
+++ b/libgo/go/internal/poll/sock_cloexec.go
@@ -5,7 +5,7 @@
 // This file implements sysSocket and accept for platforms that
 // provide a fast path for setting SetNonblock and CloseOnExec.
 
-// +build dragonfly freebsd linux
+// +build dragonfly freebsd linux netbsd openbsd
 
 package poll
 
diff --git a/libgo/go/internal/poll/splice_linux.go b/libgo/go/internal/poll/splice_linux.go
new file mode 100644
index 0000000..aa237e5
--- /dev/null
+++ b/libgo/go/internal/poll/splice_linux.go
@@ -0,0 +1,183 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package poll
+
+import (
+	"sync/atomic"
+	"syscall"
+	"unsafe"
+)
+
+const (
+	// spliceNonblock makes calls to splice(2) non-blocking.
+	spliceNonblock = 0x2
+
+	// maxSpliceSize is the maximum amount of data Splice asks
+	// the kernel to move in a single call to splice(2).
+	maxSpliceSize = 4 << 20
+)
+
+// Splice transfers at most remain bytes of data from src to dst, using the
+// splice system call to minimize copies of data from and to userspace.
+//
+// Splice creates a temporary pipe, to serve as a buffer for the data transfer.
+// src and dst must both be stream-oriented sockets.
+//
+// If err != nil, sc is the system call which caused the error.
+func Splice(dst, src *FD, remain int64) (written int64, handled bool, sc string, err error) {
+	prfd, pwfd, sc, err := newTempPipe()
+	if err != nil {
+		return 0, false, sc, err
+	}
+	defer destroyTempPipe(prfd, pwfd)
+	// From here on, the operation should be considered handled,
+	// even if Splice doesn't transfer any data.
+	var inPipe, n int
+	for err == nil && remain > 0 {
+		max := maxSpliceSize
+		if int64(max) > remain {
+			max = int(remain)
+		}
+		inPipe, err = spliceDrain(pwfd, src, max)
+		// spliceDrain should never return EAGAIN, so if err != nil,
+		// Splice cannot continue. If inPipe == 0 && err == nil,
+		// src is at EOF, and the transfer is complete.
+		if err != nil || (inPipe == 0 && err == nil) {
+			break
+		}
+		n, err = splicePump(dst, prfd, inPipe)
+		if n > 0 {
+			written += int64(n)
+			remain -= int64(n)
+		}
+	}
+	if err != nil {
+		return written, true, "splice", err
+	}
+	return written, true, "", nil
+}
+
+// spliceDrain moves data from a socket to a pipe.
+//
+// Invariant: when entering spliceDrain, the pipe is empty. It is either in its
+// initial state, or splicePump has emptied it previously.
+//
+// Given this, spliceDrain can reasonably assume that the pipe is ready for
+// writing, so if splice returns EAGAIN, it must be because the socket is not
+// ready for reading.
+//
+// If spliceDrain returns (0, nil), src is at EOF.
+func spliceDrain(pipefd int, sock *FD, max int) (int, error) {
+	if err := sock.readLock(); err != nil {
+		return 0, err
+	}
+	defer sock.readUnlock()
+	if err := sock.pd.prepareRead(sock.isFile); err != nil {
+		return 0, err
+	}
+	for {
+		n, err := splice(pipefd, sock.Sysfd, max, spliceNonblock)
+		if err != syscall.EAGAIN {
+			return n, err
+		}
+		if err := sock.pd.waitRead(sock.isFile); err != nil {
+			return n, err
+		}
+	}
+}
+
+// splicePump moves all the buffered data from a pipe to a socket.
+//
+// Invariant: when entering splicePump, there are exactly inPipe
+// bytes of data in the pipe, from a previous call to spliceDrain.
+//
+// By analogy to the condition from spliceDrain, splicePump
+// only needs to poll the socket for readiness, if splice returns
+// EAGAIN.
+//
+// If splicePump cannot move all the data in a single call to
+// splice(2), it loops over the buffered data until it has written
+// all of it to the socket. This behavior is similar to the Write
+// step of an io.Copy in userspace.
+func splicePump(sock *FD, pipefd int, inPipe int) (int, error) {
+	if err := sock.writeLock(); err != nil {
+		return 0, err
+	}
+	defer sock.writeUnlock()
+	if err := sock.pd.prepareWrite(sock.isFile); err != nil {
+		return 0, err
+	}
+	written := 0
+	for inPipe > 0 {
+		n, err := splice(sock.Sysfd, pipefd, inPipe, spliceNonblock)
+		// Here, the condition n == 0 && err == nil should never be
+		// observed, since Splice controls the write side of the pipe.
+		if n > 0 {
+			inPipe -= n
+			written += n
+			continue
+		}
+		if err != syscall.EAGAIN {
+			return written, err
+		}
+		if err := sock.pd.waitWrite(sock.isFile); err != nil {
+			return written, err
+		}
+	}
+	return written, nil
+}
+
+// splice wraps the splice system call. Since the current implementation
+// only uses splice on sockets and pipes, the offset arguments are unused.
+// splice returns int instead of int64, because callers never ask it to
+// move more data in a single call than can fit in an int32.
+func splice(out int, in int, max int, flags int) (int, error) {
+	n, err := syscall.Splice(in, nil, out, nil, max, flags)
+	return int(n), err
+}
+
+var disableSplice unsafe.Pointer
+
+// newTempPipe sets up a temporary pipe for a splice operation.
+func newTempPipe() (prfd, pwfd int, sc string, err error) {
+	p := (*bool)(atomic.LoadPointer(&disableSplice))
+	if p != nil && *p {
+		return -1, -1, "splice", syscall.EINVAL
+	}
+
+	var fds [2]int
+	// pipe2 was added in 2.6.27 and our minimum requirement is 2.6.23, so it
+	// might not be implemented. Falling back to pipe is possible, but prior to
+	// 2.6.29 splice returns -EAGAIN instead of 0 when the connection is
+	// closed.
+	const flags = syscall.O_CLOEXEC | syscall.O_NONBLOCK
+	if err := syscall.Pipe2(fds[:], flags); err != nil {
+		return -1, -1, "pipe2", err
+	}
+
+	if p == nil {
+		p = new(bool)
+		defer atomic.StorePointer(&disableSplice, unsafe.Pointer(p))
+
+		// F_GETPIPE_SZ was added in 2.6.35, which does not have the -EAGAIN bug.
+		if _, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fds[0]), syscall.F_GETPIPE_SZ, 0); errno != 0 {
+			*p = true
+			destroyTempPipe(fds[0], fds[1])
+			return -1, -1, "fcntl", errno
+		}
+	}
+
+	return fds[0], fds[1], "", nil
+}
+
+// destroyTempPipe destroys a temporary pipe.
+func destroyTempPipe(prfd, pwfd int) error {
+	err := CloseFunc(prfd)
+	err1 := CloseFunc(pwfd)
+	if err == nil {
+		return err1
+	}
+	return err
+}
diff --git a/libgo/go/internal/poll/sys_cloexec.go b/libgo/go/internal/poll/sys_cloexec.go
index fb5f2bc..64e4612 100644
--- a/libgo/go/internal/poll/sys_cloexec.go
+++ b/libgo/go/internal/poll/sys_cloexec.go
@@ -5,7 +5,7 @@
 // This file implements sysSocket and accept for platforms that do not
 // provide a fast path for setting SetNonblock and CloseOnExec.
 
-// +build aix darwin nacl netbsd openbsd solaris
+// +build aix darwin js,wasm nacl solaris
 
 package poll
 
diff --git a/libgo/go/internal/syscall/unix/nonblocking.go b/libgo/go/internal/syscall/unix/nonblocking.go
new file mode 100644
index 0000000..da7f8bd
--- /dev/null
+++ b/libgo/go/internal/syscall/unix/nonblocking.go
@@ -0,0 +1,23 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package unix
+
+import (
+	"syscall"
+	_ "unsafe" // for go:linkname
+)
+
+//extern __go_fcntl
+func syscall_fcntl(fd int32, cmd int32, arg int32) int32
+
+func IsNonblock(fd int) (nonblocking bool, err error) {
+	flag := syscall_fcntl(int32(fd), syscall.F_GETFL, 0)
+	if flag < 0 {
+		return false, syscall.GetErrno()
+	}
+	return flag&syscall.O_NONBLOCK != 0, nil
+}
diff --git a/libgo/go/internal/syscall/unix/nonblocking_js.go b/libgo/go/internal/syscall/unix/nonblocking_js.go
new file mode 100644
index 0000000..a360b53
--- /dev/null
+++ b/libgo/go/internal/syscall/unix/nonblocking_js.go
@@ -0,0 +1,11 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build js,wasm
+
+package unix
+
+func IsNonblock(fd int) (nonblocking bool, err error) {
+	return false, nil
+}
diff --git a/libgo/go/internal/syscall/unix/nonblocking_nacl.go b/libgo/go/internal/syscall/unix/nonblocking_nacl.go
new file mode 100644
index 0000000..ff67c75
--- /dev/null
+++ b/libgo/go/internal/syscall/unix/nonblocking_nacl.go
@@ -0,0 +1,9 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package unix
+
+func IsNonblock(fd int) (nonblocking bool, err error) {
+	return false, nil
+}
diff --git a/libgo/go/internal/syscall/windows/exec_windows_test.go b/libgo/go/internal/syscall/windows/exec_windows_test.go
index 94fd95b..283d7ce 100644
--- a/libgo/go/internal/syscall/windows/exec_windows_test.go
+++ b/libgo/go/internal/syscall/windows/exec_windows_test.go
@@ -17,10 +17,6 @@ import (
 )
 
 func TestRunAtLowIntegrity(t *testing.T) {
-	if isWindowsXP(t) {
-		t.Skip("Windows XP does not support windows integrity levels")
-	}
-
 	if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
 		wil, err := getProcessIntegrityLevel()
 		if err != nil {
@@ -56,15 +52,6 @@ func TestRunAtLowIntegrity(t *testing.T) {
 	}
 }
 
-func isWindowsXP(t *testing.T) bool {
-	v, err := syscall.GetVersion()
-	if err != nil {
-		t.Fatalf("GetVersion failed: %v", err)
-	}
-	major := byte(v)
-	return major < 6
-}
-
 const (
 	sidWilLow = `S-1-16-4096`
 )
diff --git a/libgo/go/internal/syscall/windows/registry/key.go b/libgo/go/internal/syscall/windows/registry/key.go
index 62144d3..cc3d0c7 100644
--- a/libgo/go/internal/syscall/windows/registry/key.go
+++ b/libgo/go/internal/syscall/windows/registry/key.go
@@ -93,12 +93,10 @@ func OpenKey(k Key, path string, access uint32) (Key, error) {
 // The parameter n controls the number of returned names,
 // analogous to the way os.File.Readdirnames works.
 func (k Key) ReadSubKeyNames(n int) ([]string, error) {
-	ki, err := k.Stat()
-	if err != nil {
-		return nil, err
-	}
-	names := make([]string, 0, ki.SubKeyCount)
-	buf := make([]uint16, ki.MaxSubKeyLen+1) // extra room for terminating zero byte
+	names := make([]string, 0)
+	// Registry key size limit is 255 bytes and described there:
+	// https://msdn.microsoft.com/library/windows/desktop/ms724872.aspx
+	buf := make([]uint16, 256) //plus extra room for terminating zero byte
 loopItems:
 	for i := uint32(0); ; i++ {
 		if n > 0 {
diff --git a/libgo/go/internal/syscall/windows/registry/registry_test.go b/libgo/go/internal/syscall/windows/registry/registry_test.go
index 56069d7..c77329c 100644
--- a/libgo/go/internal/syscall/windows/registry/registry_test.go
+++ b/libgo/go/internal/syscall/windows/registry/registry_test.go
@@ -28,7 +28,7 @@ func randKeyName(prefix string) string {
 }
 
 func TestReadSubKeyNames(t *testing.T) {
-	k, err := registry.OpenKey(registry.CLASSES_ROOT, "TypeLib", registry.ENUMERATE_SUB_KEYS|registry.QUERY_VALUE)
+	k, err := registry.OpenKey(registry.CLASSES_ROOT, "TypeLib", registry.ENUMERATE_SUB_KEYS)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/libgo/go/internal/syscall/windows/registry/zsyscall_windows.go b/libgo/go/internal/syscall/windows/registry/zsyscall_windows.go
index a3a1f5f..c3f3a8a 100644
--- a/libgo/go/internal/syscall/windows/registry/zsyscall_windows.go
+++ b/libgo/go/internal/syscall/windows/registry/zsyscall_windows.go
@@ -1,4 +1,4 @@
-// MACHINE GENERATED BY 'go generate' COMMAND; DO NOT EDIT
+// Code generated by 'go generate'; DO NOT EDIT.
 
 package registry
 
diff --git a/libgo/go/internal/syscall/windows/security_windows.go b/libgo/go/internal/syscall/windows/security_windows.go
index 14ea425..4a2dfc0 100644
--- a/libgo/go/internal/syscall/windows/security_windows.go
+++ b/libgo/go/internal/syscall/windows/security_windows.go
@@ -81,3 +81,48 @@ const (
 	TokenPrimary       TokenType = 1
 	TokenImpersonation TokenType = 2
 )
+
+//sys	GetProfilesDirectory(dir *uint16, dirLen *uint32) (err error) = userenv.GetProfilesDirectoryW
+
+const (
+	LG_INCLUDE_INDIRECT  = 0x1
+	MAX_PREFERRED_LENGTH = 0xFFFFFFFF
+)
+
+type LocalGroupUserInfo0 struct {
+	Name *uint16
+}
+
+type UserInfo4 struct {
+	Name            *uint16
+	Password        *uint16
+	PasswordAge     uint32
+	Priv            uint32
+	HomeDir         *uint16
+	Comment         *uint16
+	Flags           uint32
+	ScriptPath      *uint16
+	AuthFlags       uint32
+	FullName        *uint16
+	UsrComment      *uint16
+	Parms           *uint16
+	Workstations    *uint16
+	LastLogon       uint32
+	LastLogoff      uint32
+	AcctExpires     uint32
+	MaxStorage      uint32
+	UnitsPerWeek    uint32
+	LogonHours      *byte
+	BadPwCount      uint32
+	NumLogons       uint32
+	LogonServer     *uint16
+	CountryCode     uint32
+	CodePage        uint32
+	UserSid         *syscall.SID
+	PrimaryGroupID  uint32
+	Profile         *uint16
+	HomeDirDrive    *uint16
+	PasswordExpired uint32
+}
+
+//sys	NetUserGetLocalGroups(serverName *uint16, userName *uint16, level uint32, flags uint32, buf **byte, prefMaxLen uint32, entriesRead *uint32, totalEntries *uint32) (neterr error) = netapi32.NetUserGetLocalGroups
diff --git a/libgo/go/internal/syscall/windows/symlink_windows.go b/libgo/go/internal/syscall/windows/symlink_windows.go
new file mode 100644
index 0000000..cc2163e
--- /dev/null
+++ b/libgo/go/internal/syscall/windows/symlink_windows.go
@@ -0,0 +1,14 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package windows
+
+import "syscall"
+
+const (
+	ERROR_INVALID_PARAMETER syscall.Errno = 87
+
+	// symlink support for CreateSymbolicLink() starting with Windows 10 (1703, v10.0.14972)
+	SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE = 0x2
+)
diff --git a/libgo/go/internal/syscall/windows/syscall_windows.go b/libgo/go/internal/syscall/windows/syscall_windows.go
index b531f89..66fe932 100644
--- a/libgo/go/internal/syscall/windows/syscall_windows.go
+++ b/libgo/go/internal/syscall/windows/syscall_windows.go
@@ -12,6 +12,7 @@ import (
 
 const (
 	ERROR_SHARING_VIOLATION      syscall.Errno = 32
+	ERROR_INVALID_NAME           syscall.Errno = 123
 	ERROR_NO_UNICODE_TRANSLATION syscall.Errno = 1113
 )
 
@@ -122,6 +123,7 @@ const (
 
 	WSAEMSGSIZE syscall.Errno = 10040
 
+	MSG_PEEK   = 0x2
 	MSG_TRUNC  = 0x0100
 	MSG_CTRUNC = 0x0200
 
diff --git a/libgo/go/internal/syscall/windows/zsyscall_windows.go b/libgo/go/internal/syscall/windows/zsyscall_windows.go
index bdca80c..550a8a5 100644
--- a/libgo/go/internal/syscall/windows/zsyscall_windows.go
+++ b/libgo/go/internal/syscall/windows/zsyscall_windows.go
@@ -1,4 +1,4 @@
-// MACHINE GENERATED BY 'go generate' COMMAND; DO NOT EDIT
+// Code generated by 'go generate'; DO NOT EDIT.
 
 package windows
 
@@ -41,6 +41,7 @@ var (
 	modws2_32   = syscall.NewLazyDLL(sysdll.Add("ws2_32.dll"))
 	modnetapi32 = syscall.NewLazyDLL(sysdll.Add("netapi32.dll"))
 	modadvapi32 = syscall.NewLazyDLL(sysdll.Add("advapi32.dll"))
+	moduserenv  = syscall.NewLazyDLL(sysdll.Add("userenv.dll"))
 	modpsapi    = syscall.NewLazyDLL(sysdll.Add("psapi.dll"))
 
 	procGetAdaptersAddresses      = modiphlpapi.NewProc("GetAdaptersAddresses")
@@ -62,6 +63,8 @@ var (
 	procAdjustTokenPrivileges     = modadvapi32.NewProc("AdjustTokenPrivileges")
 	procDuplicateTokenEx          = modadvapi32.NewProc("DuplicateTokenEx")
 	procSetTokenInformation       = modadvapi32.NewProc("SetTokenInformation")
+	procGetProfilesDirectoryW     = moduserenv.NewProc("GetProfilesDirectoryW")
+	procNetUserGetLocalGroups     = modnetapi32.NewProc("NetUserGetLocalGroups")
 	procGetProcessMemoryInfo      = modpsapi.NewProc("GetProcessMemoryInfo")
 )
 
@@ -287,6 +290,26 @@ func SetTokenInformation(tokenHandle syscall.Token, tokenInformationClass uint32
 	return
 }
 
+func GetProfilesDirectory(dir *uint16, dirLen *uint32) (err error) {
+	r1, _, e1 := syscall.Syscall(procGetProfilesDirectoryW.Addr(), 2, uintptr(unsafe.Pointer(dir)), uintptr(unsafe.Pointer(dirLen)), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
+func NetUserGetLocalGroups(serverName *uint16, userName *uint16, level uint32, flags uint32, buf **byte, prefMaxLen uint32, entriesRead *uint32, totalEntries *uint32) (neterr error) {
+	r0, _, _ := syscall.Syscall9(procNetUserGetLocalGroups.Addr(), 8, uintptr(unsafe.Pointer(serverName)), uintptr(unsafe.Pointer(userName)), uintptr(level), uintptr(flags), uintptr(unsafe.Pointer(buf)), uintptr(prefMaxLen), uintptr(unsafe.Pointer(entriesRead)), uintptr(unsafe.Pointer(totalEntries)), 0)
+	if r0 != 0 {
+		neterr = syscall.Errno(r0)
+	}
+	return
+}
+
 func GetProcessMemoryInfo(handle syscall.Handle, memCounters *PROCESS_MEMORY_COUNTERS, cb uint32) (err error) {
 	r1, _, e1 := syscall.Syscall(procGetProcessMemoryInfo.Addr(), 3, uintptr(handle), uintptr(unsafe.Pointer(memCounters)), uintptr(cb))
 	if r1 == 0 {
diff --git a/libgo/go/internal/testenv/testenv.go b/libgo/go/internal/testenv/testenv.go
index 87d01d2..1518690 100644
--- a/libgo/go/internal/testenv/testenv.go
+++ b/libgo/go/internal/testenv/testenv.go
@@ -48,7 +48,7 @@ func HasGoBuild() bool {
 		return false
 	}
 	switch runtime.GOOS {
-	case "android", "nacl":
+	case "android", "nacl", "js":
 		return false
 	case "darwin":
 		if strings.HasPrefix(runtime.GOARCH, "arm") {
@@ -128,7 +128,7 @@ func GoTool() (string, error) {
 // using os.StartProcess or (more commonly) exec.Command.
 func HasExec() bool {
 	switch runtime.GOOS {
-	case "nacl":
+	case "nacl", "js":
 		return false
 	case "darwin":
 		if strings.HasPrefix(runtime.GOARCH, "arm") {
@@ -166,13 +166,16 @@ func MustHaveExec(t testing.TB) {
 // HasExternalNetwork reports whether the current system can use
 // external (non-localhost) networks.
 func HasExternalNetwork() bool {
-	return !testing.Short()
+	return !testing.Short() && runtime.GOOS != "nacl" && runtime.GOOS != "js"
 }
 
 // MustHaveExternalNetwork checks that the current system can use
 // external (non-localhost) networks.
 // If not, MustHaveExternalNetwork calls t.Skip with an explanation.
 func MustHaveExternalNetwork(t testing.TB) {
+	if runtime.GOOS == "nacl" || runtime.GOOS == "js" {
+		t.Skipf("skipping test: no external network on %s", runtime.GOOS)
+	}
 	if testing.Short() {
 		t.Skipf("skipping test: no external network in -short mode")
 	}
diff --git a/libgo/go/internal/testenv/testenv_notwin.go b/libgo/go/internal/testenv/testenv_notwin.go
index 3853973..d8ce6cd 100644
--- a/libgo/go/internal/testenv/testenv_notwin.go
+++ b/libgo/go/internal/testenv/testenv_notwin.go
@@ -18,7 +18,3 @@ func hasSymlink() (ok bool, reason string) {
 
 	return true, ""
 }
-
-func IsWindowsXP() bool {
-	return false
-}
diff --git a/libgo/go/internal/testenv/testenv_windows.go b/libgo/go/internal/testenv/testenv_windows.go
index 4a7da5f..eb8d6ac 100644
--- a/libgo/go/internal/testenv/testenv_windows.go
+++ b/libgo/go/internal/testenv/testenv_windows.go
@@ -46,12 +46,3 @@ func hasSymlink() (ok bool, reason string) {
 
 	return false, ""
 }
-
-func IsWindowsXP() bool {
-	v, err := syscall.GetVersion()
-	if err != nil {
-		panic("GetVersion failed: " + err.Error())
-	}
-	major := byte(v)
-	return major < 6
-}
diff --git a/libgo/go/internal/trace/goroutines.go b/libgo/go/internal/trace/goroutines.go
index 923a157..2d7d3aa 100644
--- a/libgo/go/internal/trace/goroutines.go
+++ b/libgo/go/internal/trace/goroutines.go
@@ -4,7 +4,9 @@
 
 package trace
 
-// GDesc contains statistics about execution of a single goroutine.
+import "sort"
+
+// GDesc contains statistics and execution details of a single goroutine.
 type GDesc struct {
 	ID           uint64
 	Name         string
@@ -13,6 +15,37 @@ type GDesc struct {
 	StartTime    int64
 	EndTime      int64
 
+	// List of regions in the goroutine, sorted based on the start time.
+	Regions []*UserRegionDesc
+
+	// Statistics of execution time during the goroutine execution.
+	GExecutionStat
+
+	*gdesc // private part.
+}
+
+// UserRegionDesc represents a region and goroutine execution stats
+// while the region was active.
+type UserRegionDesc struct {
+	TaskID uint64
+	Name   string
+
+	// Region start event. Normally EvUserRegion start event or nil,
+	// but can be EvGoCreate event if the region is a synthetic
+	// region representing task inheritance from the parent goroutine.
+	Start *Event
+
+	// Region end event. Normally EvUserRegion end event or nil,
+	// but can be EvGoStop or EvGoEnd event if the goroutine
+	// terminated without explicitely ending the region.
+	End *Event
+
+	GExecutionStat
+}
+
+// GExecutionStat contains statistics about a goroutine's execution
+// during a period of time.
+type GExecutionStat struct {
 	ExecTime      int64
 	SchedWaitTime int64
 	IOTime        int64
@@ -21,8 +54,84 @@ type GDesc struct {
 	GCTime        int64
 	SweepTime     int64
 	TotalTime     int64
+}
+
+// sub returns the stats v-s.
+func (s GExecutionStat) sub(v GExecutionStat) (r GExecutionStat) {
+	r = s
+	r.ExecTime -= v.ExecTime
+	r.SchedWaitTime -= v.SchedWaitTime
+	r.IOTime -= v.IOTime
+	r.BlockTime -= v.BlockTime
+	r.SyscallTime -= v.SyscallTime
+	r.GCTime -= v.GCTime
+	r.SweepTime -= v.SweepTime
+	r.TotalTime -= v.TotalTime
+	return r
+}
+
+// snapshotStat returns the snapshot of the goroutine execution statistics.
+// This is called as we process the ordered trace event stream. lastTs and
+// activeGCStartTime are used to process pending statistics if this is called
+// before any goroutine end event.
+func (g *GDesc) snapshotStat(lastTs, activeGCStartTime int64) (ret GExecutionStat) {
+	ret = g.GExecutionStat
+
+	if g.gdesc == nil {
+		return ret // finalized GDesc. No pending state.
+	}
+
+	if activeGCStartTime != 0 { // terminating while GC is active
+		if g.CreationTime < activeGCStartTime {
+			ret.GCTime += lastTs - activeGCStartTime
+		} else {
+			// The goroutine's lifetime completely overlaps
+			// with a GC.
+			ret.GCTime += lastTs - g.CreationTime
+		}
+	}
+
+	if g.TotalTime == 0 {
+		ret.TotalTime = lastTs - g.CreationTime
+	}
+
+	if g.lastStartTime != 0 {
+		ret.ExecTime += lastTs - g.lastStartTime
+	}
+	if g.blockNetTime != 0 {
+		ret.IOTime += lastTs - g.blockNetTime
+	}
+	if g.blockSyncTime != 0 {
+		ret.BlockTime += lastTs - g.blockSyncTime
+	}
+	if g.blockSyscallTime != 0 {
+		ret.SyscallTime += lastTs - g.blockSyscallTime
+	}
+	if g.blockSchedTime != 0 {
+		ret.SchedWaitTime += lastTs - g.blockSchedTime
+	}
+	if g.blockSweepTime != 0 {
+		ret.SweepTime += lastTs - g.blockSweepTime
+	}
+	return ret
+}
 
-	*gdesc // private part
+// finalize is called when processing a goroutine end event or at
+// the end of trace processing. This finalizes the execution stat
+// and any active regions in the goroutine, in which case trigger is nil.
+func (g *GDesc) finalize(lastTs, activeGCStartTime int64, trigger *Event) {
+	if trigger != nil {
+		g.EndTime = trigger.Ts
+	}
+	finalStat := g.snapshotStat(lastTs, activeGCStartTime)
+
+	g.GExecutionStat = finalStat
+	for _, s := range g.activeRegions {
+		s.End = trigger
+		s.GExecutionStat = finalStat.sub(s.GExecutionStat)
+		g.Regions = append(g.Regions, s)
+	}
+	*(g.gdesc) = gdesc{}
 }
 
 // gdesc is a private part of GDesc that is required only during analysis.
@@ -34,19 +143,34 @@ type gdesc struct {
 	blockSweepTime   int64
 	blockGCTime      int64
 	blockSchedTime   int64
+
+	activeRegions []*UserRegionDesc // stack of active regions
 }
 
 // GoroutineStats generates statistics for all goroutines in the trace.
 func GoroutineStats(events []*Event) map[uint64]*GDesc {
 	gs := make(map[uint64]*GDesc)
 	var lastTs int64
-	var gcStartTime int64
+	var gcStartTime int64 // gcStartTime == 0 indicates gc is inactive.
 	for _, ev := range events {
 		lastTs = ev.Ts
 		switch ev.Type {
 		case EvGoCreate:
 			g := &GDesc{ID: ev.Args[0], CreationTime: ev.Ts, gdesc: new(gdesc)}
 			g.blockSchedTime = ev.Ts
+			// When a goroutine is newly created, inherit the
+			// task of the active region. For ease handling of
+			// this case, we create a fake region description with
+			// the task id.
+			if creatorG := gs[ev.G]; creatorG != nil && len(creatorG.gdesc.activeRegions) > 0 {
+				regions := creatorG.gdesc.activeRegions
+				s := regions[len(regions)-1]
+				if s.TaskID != 0 {
+					g.gdesc.activeRegions = []*UserRegionDesc{
+						{TaskID: s.TaskID, Start: ev},
+					}
+				}
+			}
 			gs[g.ID] = g
 		case EvGoStart, EvGoStartLabel:
 			g := gs[ev.G]
@@ -64,28 +188,31 @@ func GoroutineStats(events []*Event) map[uint64]*GDesc {
 			}
 		case EvGoEnd, EvGoStop:
 			g := gs[ev.G]
-			g.ExecTime += ev.Ts - g.lastStartTime
-			g.TotalTime = ev.Ts - g.CreationTime
-			g.EndTime = ev.Ts
+			g.finalize(ev.Ts, gcStartTime, ev)
 		case EvGoBlockSend, EvGoBlockRecv, EvGoBlockSelect,
 			EvGoBlockSync, EvGoBlockCond:
 			g := gs[ev.G]
 			g.ExecTime += ev.Ts - g.lastStartTime
+			g.lastStartTime = 0
 			g.blockSyncTime = ev.Ts
 		case EvGoSched, EvGoPreempt:
 			g := gs[ev.G]
 			g.ExecTime += ev.Ts - g.lastStartTime
+			g.lastStartTime = 0
 			g.blockSchedTime = ev.Ts
 		case EvGoSleep, EvGoBlock:
 			g := gs[ev.G]
 			g.ExecTime += ev.Ts - g.lastStartTime
+			g.lastStartTime = 0
 		case EvGoBlockNet:
 			g := gs[ev.G]
 			g.ExecTime += ev.Ts - g.lastStartTime
+			g.lastStartTime = 0
 			g.blockNetTime = ev.Ts
 		case EvGoBlockGC:
 			g := gs[ev.G]
 			g.ExecTime += ev.Ts - g.lastStartTime
+			g.lastStartTime = 0
 			g.blockGCTime = ev.Ts
 		case EvGoUnblock:
 			g := gs[ev.Args[0]]
@@ -101,6 +228,7 @@ func GoroutineStats(events []*Event) map[uint64]*GDesc {
 		case EvGoSysBlock:
 			g := gs[ev.G]
 			g.ExecTime += ev.Ts - g.lastStartTime
+			g.lastStartTime = 0
 			g.blockSyscallTime = ev.Ts
 		case EvGoSysExit:
 			g := gs[ev.G]
@@ -125,36 +253,62 @@ func GoroutineStats(events []*Event) map[uint64]*GDesc {
 			gcStartTime = ev.Ts
 		case EvGCDone:
 			for _, g := range gs {
-				if g.EndTime == 0 {
+				if g.EndTime != 0 {
+					continue
+				}
+				if gcStartTime < g.CreationTime {
+					g.GCTime += ev.Ts - g.CreationTime
+				} else {
 					g.GCTime += ev.Ts - gcStartTime
 				}
 			}
+			gcStartTime = 0 // indicates gc is inactive.
+		case EvUserRegion:
+			g := gs[ev.G]
+			switch mode := ev.Args[1]; mode {
+			case 0: // region start
+				g.activeRegions = append(g.activeRegions, &UserRegionDesc{
+					Name:           ev.SArgs[0],
+					TaskID:         ev.Args[0],
+					Start:          ev,
+					GExecutionStat: g.snapshotStat(lastTs, gcStartTime),
+				})
+			case 1: // region end
+				var sd *UserRegionDesc
+				if regionStk := g.activeRegions; len(regionStk) > 0 {
+					n := len(regionStk)
+					sd = regionStk[n-1]
+					regionStk = regionStk[:n-1] // pop
+					g.activeRegions = regionStk
+				} else {
+					sd = &UserRegionDesc{
+						Name:   ev.SArgs[0],
+						TaskID: ev.Args[0],
+					}
+				}
+				sd.GExecutionStat = g.snapshotStat(lastTs, gcStartTime).sub(sd.GExecutionStat)
+				sd.End = ev
+				g.Regions = append(g.Regions, sd)
+			}
 		}
 	}
 
 	for _, g := range gs {
-		if g.TotalTime == 0 {
-			g.TotalTime = lastTs - g.CreationTime
-		}
-		if g.EndTime == 0 {
-			g.EndTime = lastTs
-		}
-		if g.blockNetTime != 0 {
-			g.IOTime += lastTs - g.blockNetTime
-			g.blockNetTime = 0
-		}
-		if g.blockSyncTime != 0 {
-			g.BlockTime += lastTs - g.blockSyncTime
-			g.blockSyncTime = 0
-		}
-		if g.blockSyscallTime != 0 {
-			g.SyscallTime += lastTs - g.blockSyscallTime
-			g.blockSyscallTime = 0
-		}
-		if g.blockSchedTime != 0 {
-			g.SchedWaitTime += lastTs - g.blockSchedTime
-			g.blockSchedTime = 0
-		}
+		g.finalize(lastTs, gcStartTime, nil)
+
+		// sort based on region start time
+		sort.Slice(g.Regions, func(i, j int) bool {
+			x := g.Regions[i].Start
+			y := g.Regions[j].Start
+			if x == nil {
+				return true
+			}
+			if y == nil {
+				return false
+			}
+			return x.Ts < y.Ts
+		})
+
 		g.gdesc = nil
 	}
 
diff --git a/libgo/go/internal/trace/parser.go b/libgo/go/internal/trace/parser.go
index c7954f0..c371ff3 100644
--- a/libgo/go/internal/trace/parser.go
+++ b/libgo/go/internal/trace/parser.go
@@ -55,6 +55,8 @@ type Event struct {
 	// for blocking GoSysCall: the associated GoSysExit
 	// for GoSysExit: the next GoStart
 	// for GCMarkAssistStart: the associated GCMarkAssistDone
+	// for UserTaskCreate: the UserTaskEnd
+	// for UserRegion: if the start region, the corresponding UserRegion end event
 	Link *Event
 }
 
@@ -106,10 +108,7 @@ func parse(r io.Reader, bin string) (int, ParseResult, error) {
 	if err != nil {
 		return 0, ParseResult{}, err
 	}
-	events, err = removeFutile(events)
-	if err != nil {
-		return 0, ParseResult{}, err
-	}
+	events = removeFutile(events)
 	err = postProcessTrace(ver, events)
 	if err != nil {
 		return 0, ParseResult{}, err
@@ -130,9 +129,10 @@ func parse(r io.Reader, bin string) (int, ParseResult, error) {
 
 // rawEvent is a helper type used during parsing.
 type rawEvent struct {
-	off  int
-	typ  byte
-	args []uint64
+	off   int
+	typ   byte
+	args  []uint64
+	sargs []string
 }
 
 // readTrace does wire-format parsing and verification.
@@ -150,7 +150,7 @@ func readTrace(r io.Reader) (ver int, events []rawEvent, strings map[uint64]stri
 		return
 	}
 	switch ver {
-	case 1005, 1007, 1008, 1009, 1010:
+	case 1005, 1007, 1008, 1009, 1010, 1011:
 		// Note: When adding a new version, add canned traces
 		// from the old version to the test suite using mkcanned.bash.
 		break
@@ -259,11 +259,34 @@ func readTrace(r io.Reader) (ver int, events []rawEvent, strings map[uint64]stri
 				return
 			}
 		}
+		switch ev.typ {
+		case EvUserLog: // EvUserLog records are followed by a value string of length ev.args[len(ev.args)-1]
+			var s string
+			s, off, err = readStr(r, off)
+			ev.sargs = append(ev.sargs, s)
+		}
 		events = append(events, ev)
 	}
 	return
 }
 
+func readStr(r io.Reader, off0 int) (s string, off int, err error) {
+	var sz uint64
+	sz, off, err = readVal(r, off0)
+	if err != nil || sz == 0 {
+		return "", off, err
+	}
+	if sz > 1e6 {
+		return "", off, fmt.Errorf("string at offset %d is too large (len=%d)", off, sz)
+	}
+	buf := make([]byte, sz)
+	n, err := io.ReadFull(r, buf)
+	if err != nil || sz != uint64(n) {
+		return "", off + n, fmt.Errorf("failed to read trace at offset %d: read %v, want %v, error %v", off, n, sz, err)
+	}
+	return string(buf), off + n, nil
+}
+
 // parseHeader parses trace header of the form "go 1.7 trace\x00\x00\x00\x00"
 // and returns parsed version as 1007.
 func parseHeader(buf []byte) (int, error) {
@@ -416,6 +439,15 @@ func parseEvents(ver int, rawEvents []rawEvent, strings map[uint64]string) (even
 				lastG = 0
 			case EvGoSysExit, EvGoWaiting, EvGoInSyscall:
 				e.G = e.Args[0]
+			case EvUserTaskCreate:
+				// e.Args 0: taskID, 1:parentID, 2:nameID
+				e.SArgs = []string{strings[e.Args[2]]}
+			case EvUserRegion:
+				// e.Args 0: taskID, 1: mode, 2:nameID
+				e.SArgs = []string{strings[e.Args[2]]}
+			case EvUserLog:
+				// e.Args 0: taskID, 1:keyID, 2: stackID
+				e.SArgs = []string{strings[e.Args[1]], raw.sargs[0]}
 			}
 			batches[lastP] = append(batches[lastP], e)
 		}
@@ -470,7 +502,7 @@ func parseEvents(ver int, rawEvents []rawEvent, strings map[uint64]string) (even
 // ahead and acquired the mutex before the first goroutine is scheduled,
 // so the first goroutine has to block again. Such wakeups happen on buffered
 // channels and sync.Mutex, but are generally not interesting for end user.
-func removeFutile(events []*Event) ([]*Event, error) {
+func removeFutile(events []*Event) []*Event {
 	// Two non-trivial aspects:
 	// 1. A goroutine can be preempted during a futile wakeup and migrate to another P.
 	//	We want to remove all of that.
@@ -517,7 +549,7 @@ func removeFutile(events []*Event) ([]*Event, error) {
 			newEvents = append(newEvents, ev)
 		}
 	}
-	return newEvents, nil
+	return newEvents
 }
 
 // ErrTimeOrder is returned by Parse when the trace contains
@@ -551,6 +583,8 @@ func postProcessTrace(ver int, events []*Event) error {
 
 	gs := make(map[uint64]gdesc)
 	ps := make(map[int]pdesc)
+	tasks := make(map[uint64]*Event)           // task id to task creation events
+	activeRegions := make(map[uint64][]*Event) // goroutine id to stack of regions
 	gs[0] = gdesc{state: gRunning}
 	var evGC, evSTW *Event
 
@@ -695,6 +729,15 @@ func postProcessTrace(ver int, events []*Event) error {
 			g.evStart = nil
 			g.state = gDead
 			p.g = 0
+
+			if ev.Type == EvGoEnd { // flush all active regions
+				regions := activeRegions[ev.G]
+				for _, s := range regions {
+					s.Link = ev
+				}
+				delete(activeRegions, ev.G)
+			}
+
 		case EvGoSched, EvGoPreempt:
 			if err := checkRunning(p, g, ev, false); err != nil {
 				return err
@@ -756,6 +799,42 @@ func postProcessTrace(ver int, events []*Event) error {
 			g.evStart.Link = ev
 			g.evStart = nil
 			p.g = 0
+		case EvUserTaskCreate:
+			taskid := ev.Args[0]
+			if prevEv, ok := tasks[taskid]; ok {
+				return fmt.Errorf("task id conflicts (id:%d), %q vs %q", taskid, ev, prevEv)
+			}
+			tasks[ev.Args[0]] = ev
+		case EvUserTaskEnd:
+			taskid := ev.Args[0]
+			if taskCreateEv, ok := tasks[taskid]; ok {
+				taskCreateEv.Link = ev
+				delete(tasks, taskid)
+			}
+		case EvUserRegion:
+			mode := ev.Args[1]
+			regions := activeRegions[ev.G]
+			if mode == 0 { // region start
+				activeRegions[ev.G] = append(regions, ev) // push
+			} else if mode == 1 { // region end
+				n := len(regions)
+				if n > 0 { // matching region start event is in the trace.
+					s := regions[n-1]
+					if s.Args[0] != ev.Args[0] || s.SArgs[0] != ev.SArgs[0] { // task id, region name mismatch
+						return fmt.Errorf("misuse of region in goroutine %d: span end %q when the inner-most active span start event is %q", ev.G, ev, s)
+					}
+					// Link region start event with span end event
+					s.Link = ev
+
+					if n > 1 {
+						activeRegions[ev.G] = regions[:n-1]
+					} else {
+						delete(activeRegions, ev.G)
+					}
+				}
+			} else {
+				return fmt.Errorf("invalid user region mode: %q", ev)
+			}
 		}
 
 		gs[ev.G] = g
@@ -869,12 +948,20 @@ func Print(events []*Event) {
 
 // PrintEvent dumps the event to stdout. For debugging.
 func PrintEvent(ev *Event) {
+	fmt.Printf("%s\n", ev)
+}
+
+func (ev *Event) String() string {
 	desc := EventDescriptions[ev.Type]
-	fmt.Printf("%v %v p=%v g=%v off=%v", ev.Ts, desc.Name, ev.P, ev.G, ev.Off)
+	w := new(bytes.Buffer)
+	fmt.Fprintf(w, "%v %v p=%v g=%v off=%v", ev.Ts, desc.Name, ev.P, ev.G, ev.Off)
 	for i, a := range desc.Args {
-		fmt.Printf(" %v=%v", a, ev.Args[i])
+		fmt.Fprintf(w, " %v=%v", a, ev.Args[i])
+	}
+	for i, a := range desc.SArgs {
+		fmt.Fprintf(w, " %v=%v", a, ev.SArgs[i])
 	}
-	fmt.Printf("\n")
+	return w.String()
 }
 
 // argNum returns total number of args for the event accounting for timestamps,
@@ -967,7 +1054,11 @@ const (
 	EvGoBlockGC         = 42 // goroutine blocks on GC assist [timestamp, stack]
 	EvGCMarkAssistStart = 43 // GC mark assist start [timestamp, stack]
 	EvGCMarkAssistDone  = 44 // GC mark assist done [timestamp]
-	EvCount             = 45
+	EvUserTaskCreate    = 45 // trace.NewContext [timestamp, internal task id, internal parent id, stack, name string]
+	EvUserTaskEnd       = 46 // end of task [timestamp, internal task id, stack]
+	EvUserRegion        = 47 // trace.WithRegion [timestamp, internal task id, mode(0:start, 1:end), stack, name string]
+	EvUserLog           = 48 // trace.Log [timestamp, internal id, key string id, stack, value string]
+	EvCount             = 49
 )
 
 var EventDescriptions = [EvCount]struct {
@@ -975,50 +1066,55 @@ var EventDescriptions = [EvCount]struct {
 	minVersion int
 	Stack      bool
 	Args       []string
+	SArgs      []string // string arguments
 }{
-	EvNone:              {"None", 1005, false, []string{}},
-	EvBatch:             {"Batch", 1005, false, []string{"p", "ticks"}}, // in 1.5 format it was {"p", "seq", "ticks"}
-	EvFrequency:         {"Frequency", 1005, false, []string{"freq"}},   // in 1.5 format it was {"freq", "unused"}
-	EvStack:             {"Stack", 1005, false, []string{"id", "siz"}},
-	EvGomaxprocs:        {"Gomaxprocs", 1005, true, []string{"procs"}},
-	EvProcStart:         {"ProcStart", 1005, false, []string{"thread"}},
-	EvProcStop:          {"ProcStop", 1005, false, []string{}},
-	EvGCStart:           {"GCStart", 1005, true, []string{"seq"}}, // in 1.5 format it was {}
-	EvGCDone:            {"GCDone", 1005, false, []string{}},
-	EvGCSTWStart:        {"GCSTWStart", 1005, false, []string{"kind"}}, // <= 1.9, args was {} (implicitly {0})
-	EvGCSTWDone:         {"GCSTWDone", 1005, false, []string{}},
-	EvGCSweepStart:      {"GCSweepStart", 1005, true, []string{}},
-	EvGCSweepDone:       {"GCSweepDone", 1005, false, []string{"swept", "reclaimed"}}, // before 1.9, format was {}
-	EvGoCreate:          {"GoCreate", 1005, true, []string{"g", "stack"}},
-	EvGoStart:           {"GoStart", 1005, false, []string{"g", "seq"}}, // in 1.5 format it was {"g"}
-	EvGoEnd:             {"GoEnd", 1005, false, []string{}},
-	EvGoStop:            {"GoStop", 1005, true, []string{}},
-	EvGoSched:           {"GoSched", 1005, true, []string{}},
-	EvGoPreempt:         {"GoPreempt", 1005, true, []string{}},
-	EvGoSleep:           {"GoSleep", 1005, true, []string{}},
-	EvGoBlock:           {"GoBlock", 1005, true, []string{}},
-	EvGoUnblock:         {"GoUnblock", 1005, true, []string{"g", "seq"}}, // in 1.5 format it was {"g"}
-	EvGoBlockSend:       {"GoBlockSend", 1005, true, []string{}},
-	EvGoBlockRecv:       {"GoBlockRecv", 1005, true, []string{}},
-	EvGoBlockSelect:     {"GoBlockSelect", 1005, true, []string{}},
-	EvGoBlockSync:       {"GoBlockSync", 1005, true, []string{}},
-	EvGoBlockCond:       {"GoBlockCond", 1005, true, []string{}},
-	EvGoBlockNet:        {"GoBlockNet", 1005, true, []string{}},
-	EvGoSysCall:         {"GoSysCall", 1005, true, []string{}},
-	EvGoSysExit:         {"GoSysExit", 1005, false, []string{"g", "seq", "ts"}},
-	EvGoSysBlock:        {"GoSysBlock", 1005, false, []string{}},
-	EvGoWaiting:         {"GoWaiting", 1005, false, []string{"g"}},
-	EvGoInSyscall:       {"GoInSyscall", 1005, false, []string{"g"}},
-	EvHeapAlloc:         {"HeapAlloc", 1005, false, []string{"mem"}},
-	EvNextGC:            {"NextGC", 1005, false, []string{"mem"}},
-	EvTimerGoroutine:    {"TimerGoroutine", 1005, false, []string{"g"}}, // in 1.5 format it was {"g", "unused"}
-	EvFutileWakeup:      {"FutileWakeup", 1005, false, []string{}},
-	EvString:            {"String", 1007, false, []string{}},
-	EvGoStartLocal:      {"GoStartLocal", 1007, false, []string{"g"}},
-	EvGoUnblockLocal:    {"GoUnblockLocal", 1007, true, []string{"g"}},
-	EvGoSysExitLocal:    {"GoSysExitLocal", 1007, false, []string{"g", "ts"}},
-	EvGoStartLabel:      {"GoStartLabel", 1008, false, []string{"g", "seq", "label"}},
-	EvGoBlockGC:         {"GoBlockGC", 1008, true, []string{}},
-	EvGCMarkAssistStart: {"GCMarkAssistStart", 1009, true, []string{}},
-	EvGCMarkAssistDone:  {"GCMarkAssistDone", 1009, false, []string{}},
+	EvNone:              {"None", 1005, false, []string{}, nil},
+	EvBatch:             {"Batch", 1005, false, []string{"p", "ticks"}, nil}, // in 1.5 format it was {"p", "seq", "ticks"}
+	EvFrequency:         {"Frequency", 1005, false, []string{"freq"}, nil},   // in 1.5 format it was {"freq", "unused"}
+	EvStack:             {"Stack", 1005, false, []string{"id", "siz"}, nil},
+	EvGomaxprocs:        {"Gomaxprocs", 1005, true, []string{"procs"}, nil},
+	EvProcStart:         {"ProcStart", 1005, false, []string{"thread"}, nil},
+	EvProcStop:          {"ProcStop", 1005, false, []string{}, nil},
+	EvGCStart:           {"GCStart", 1005, true, []string{"seq"}, nil}, // in 1.5 format it was {}
+	EvGCDone:            {"GCDone", 1005, false, []string{}, nil},
+	EvGCSTWStart:        {"GCSTWStart", 1005, false, []string{"kindid"}, []string{"kind"}}, // <= 1.9, args was {} (implicitly {0})
+	EvGCSTWDone:         {"GCSTWDone", 1005, false, []string{}, nil},
+	EvGCSweepStart:      {"GCSweepStart", 1005, true, []string{}, nil},
+	EvGCSweepDone:       {"GCSweepDone", 1005, false, []string{"swept", "reclaimed"}, nil}, // before 1.9, format was {}
+	EvGoCreate:          {"GoCreate", 1005, true, []string{"g", "stack"}, nil},
+	EvGoStart:           {"GoStart", 1005, false, []string{"g", "seq"}, nil}, // in 1.5 format it was {"g"}
+	EvGoEnd:             {"GoEnd", 1005, false, []string{}, nil},
+	EvGoStop:            {"GoStop", 1005, true, []string{}, nil},
+	EvGoSched:           {"GoSched", 1005, true, []string{}, nil},
+	EvGoPreempt:         {"GoPreempt", 1005, true, []string{}, nil},
+	EvGoSleep:           {"GoSleep", 1005, true, []string{}, nil},
+	EvGoBlock:           {"GoBlock", 1005, true, []string{}, nil},
+	EvGoUnblock:         {"GoUnblock", 1005, true, []string{"g", "seq"}, nil}, // in 1.5 format it was {"g"}
+	EvGoBlockSend:       {"GoBlockSend", 1005, true, []string{}, nil},
+	EvGoBlockRecv:       {"GoBlockRecv", 1005, true, []string{}, nil},
+	EvGoBlockSelect:     {"GoBlockSelect", 1005, true, []string{}, nil},
+	EvGoBlockSync:       {"GoBlockSync", 1005, true, []string{}, nil},
+	EvGoBlockCond:       {"GoBlockCond", 1005, true, []string{}, nil},
+	EvGoBlockNet:        {"GoBlockNet", 1005, true, []string{}, nil},
+	EvGoSysCall:         {"GoSysCall", 1005, true, []string{}, nil},
+	EvGoSysExit:         {"GoSysExit", 1005, false, []string{"g", "seq", "ts"}, nil},
+	EvGoSysBlock:        {"GoSysBlock", 1005, false, []string{}, nil},
+	EvGoWaiting:         {"GoWaiting", 1005, false, []string{"g"}, nil},
+	EvGoInSyscall:       {"GoInSyscall", 1005, false, []string{"g"}, nil},
+	EvHeapAlloc:         {"HeapAlloc", 1005, false, []string{"mem"}, nil},
+	EvNextGC:            {"NextGC", 1005, false, []string{"mem"}, nil},
+	EvTimerGoroutine:    {"TimerGoroutine", 1005, false, []string{"g"}, nil}, // in 1.5 format it was {"g", "unused"}
+	EvFutileWakeup:      {"FutileWakeup", 1005, false, []string{}, nil},
+	EvString:            {"String", 1007, false, []string{}, nil},
+	EvGoStartLocal:      {"GoStartLocal", 1007, false, []string{"g"}, nil},
+	EvGoUnblockLocal:    {"GoUnblockLocal", 1007, true, []string{"g"}, nil},
+	EvGoSysExitLocal:    {"GoSysExitLocal", 1007, false, []string{"g", "ts"}, nil},
+	EvGoStartLabel:      {"GoStartLabel", 1008, false, []string{"g", "seq", "labelid"}, []string{"label"}},
+	EvGoBlockGC:         {"GoBlockGC", 1008, true, []string{}, nil},
+	EvGCMarkAssistStart: {"GCMarkAssistStart", 1009, true, []string{}, nil},
+	EvGCMarkAssistDone:  {"GCMarkAssistDone", 1009, false, []string{}, nil},
+	EvUserTaskCreate:    {"UserTaskCreate", 1011, true, []string{"taskid", "pid", "typeid"}, []string{"name"}},
+	EvUserTaskEnd:       {"UserTaskEnd", 1011, true, []string{"taskid"}, nil},
+	EvUserRegion:        {"UserRegion", 1011, true, []string{"taskid", "mode", "typeid"}, []string{"name"}},
+	EvUserLog:           {"UserLog", 1011, true, []string{"id", "keyid"}, []string{"category", "message"}},
 }