libgo: update to go1.15rc1

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/245157

3 files changed, 97 insertions, 4 deletions

diff --git a/libgo/go/hash/crc32/crc32_s390x.go b/libgo/go/hash/crc32/crc32_s390x.go
index 8815c70..c82ef80 100644
--- a/libgo/go/hash/crc32/crc32_s390x.go
+++ b/libgo/go/hash/crc32/crc32_s390x.go
@@ -6,16 +6,16 @@
 
 package crc32
 
+import "internal/cpu"
+
 const (
 	vxMinLen    = 64
 	vxAlignMask = 15 // align to 16 bytes
 )
 
-// hasVectorFacility reports whether the machine has the z/Architecture
+// hasVX reports whether the machine has the z/Architecture
 // vector facility installed and enabled.
-func hasVectorFacility() bool
-
-var hasVX = hasVectorFacility()
+var hasVX = cpu.S390X.HasVX
 
 // vectorizedCastagnoli implements CRC32 using vector instructions.
 // It is defined in crc32_s390x.s.
diff --git a/libgo/go/hash/maphash/example_test.go b/libgo/go/hash/maphash/example_test.go
new file mode 100644
index 0000000..78690fd
--- /dev/null
+++ b/libgo/go/hash/maphash/example_test.go
@@ -0,0 +1,37 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package maphash_test
+
+import (
+	"fmt"
+	"hash/maphash"
+)
+
+func Example() {
+	// The zero Hash value is valid and ready to use; setting an
+	// initial seed is not necessary.
+	var h maphash.Hash
+
+	// Add a string to the hash, and print the current hash value.
+	h.WriteString("hello, ")
+	fmt.Printf("%#x\n", h.Sum64())
+
+	// Append additional data (in the form of a byte array).
+	h.Write([]byte{'w', 'o', 'r', 'l', 'd'})
+	fmt.Printf("%#x\n", h.Sum64())
+
+	// Reset discards all data previously added to the Hash, without
+	// changing its seed.
+	h.Reset()
+
+	// Use SetSeed to create a new Hash h2 which will behave
+	// identically to h.
+	var h2 maphash.Hash
+	h2.SetSeed(h.Seed())
+
+	h.WriteString("same")
+	h2.WriteString("same")
+	fmt.Printf("%#x == %#x\n", h.Sum64(), h2.Sum64())
+}
diff --git a/libgo/go/hash/maphash/maphash_test.go b/libgo/go/hash/maphash/maphash_test.go
index 0164a9e..caea43a 100644
--- a/libgo/go/hash/maphash/maphash_test.go
+++ b/libgo/go/hash/maphash/maphash_test.go
@@ -106,6 +106,62 @@ func TestRepeat(t *testing.T) {
 	}
 }
 
+func TestSeedFromSum64(t *testing.T) {
+	h1 := new(Hash)
+	h1.WriteString("foo")
+	x := h1.Sum64() // seed generated here
+	h2 := new(Hash)
+	h2.SetSeed(h1.Seed())
+	h2.WriteString("foo")
+	y := h2.Sum64()
+	if x != y {
+		t.Errorf("hashes don't match: want %x, got %x", x, y)
+	}
+}
+
+func TestSeedFromSeed(t *testing.T) {
+	h1 := new(Hash)
+	h1.WriteString("foo")
+	_ = h1.Seed() // seed generated here
+	x := h1.Sum64()
+	h2 := new(Hash)
+	h2.SetSeed(h1.Seed())
+	h2.WriteString("foo")
+	y := h2.Sum64()
+	if x != y {
+		t.Errorf("hashes don't match: want %x, got %x", x, y)
+	}
+}
+
+func TestSeedFromFlush(t *testing.T) {
+	b := make([]byte, 65)
+	h1 := new(Hash)
+	h1.Write(b) // seed generated here
+	x := h1.Sum64()
+	h2 := new(Hash)
+	h2.SetSeed(h1.Seed())
+	h2.Write(b)
+	y := h2.Sum64()
+	if x != y {
+		t.Errorf("hashes don't match: want %x, got %x", x, y)
+	}
+}
+
+func TestSeedFromReset(t *testing.T) {
+	h1 := new(Hash)
+	h1.WriteString("foo")
+	h1.Reset() // seed generated here
+	h1.WriteString("foo")
+	x := h1.Sum64()
+	h2 := new(Hash)
+	h2.SetSeed(h1.Seed())
+	h2.WriteString("foo")
+	y := h2.Sum64()
+	if x != y {
+		t.Errorf("hashes don't match: want %x, got %x", x, y)
+	}
+}
+
 // Make sure a Hash implements the hash.Hash and hash.Hash64 interfaces.
 var _ hash.Hash = &Hash{}
 var _ hash.Hash64 = &Hash{}