From 7e39515dfef46a26d2af245a7d42a949efc09f80 Mon Sep 17 00:00:00 2001
From: David Sisson <dsisson@google.com>
Date: Wed, 6 Dec 2017 11:01:19 -0800
Subject: [PATCH 1/2] Changed rotation to support 32 and 64-bit architectures
 as noted in issue #2060.

---
 runtime/Go/antlr/utils.go | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/runtime/Go/antlr/utils.go b/runtime/Go/antlr/utils.go
index b9d328f10..52d16c759 100644
--- a/runtime/Go/antlr/utils.go
+++ b/runtime/Go/antlr/utils.go
@@ -353,6 +353,34 @@ func PrintArrayJavaStyle(sa []string) string {
 	return buffer.String()
 }
 
+// The following routines were lifted from bits.rotate* available in Go 1.9.
+
+const uintSize = 32 << (^uint(0) >> 32 & 1) // 32 or 64
+
+// rotateLeft returns the value of x rotated left by (k mod UintSize) bits.
+// To rotate x right by k bits, call RotateLeft(x, -k).
+func rotateLeft(x uint, k int) uint {
+  if uintSize == 32 {
+    return uint(rotateLeft32(uint32(x), k))
+  }
+  return uint(rotateLeft64(uint64(x), k))
+}
+
+// rotateLeft32 returns the value of x rotated left by (k mod 32) bits.
+func rotateLeft32(x uint32, k int) uint32 {
+  const n = 32
+  s := uint(k) & (n - 1)
+  return x<<s | x>>(n-s)
+}
+
+// rotateLeft64 returns the value of x rotated left by (k mod 64) bits.
+func rotateLeft64(x uint64, k int) uint64 {
+  const n = 64
+  s := uint(k) & (n - 1)
+  return x<<s | x>>(n-s)
+}
+
+
 // murmur hash
 const (
 	c1_32 uint = 0xCC9E2D51
@@ -367,11 +395,11 @@ func murmurInit(seed int) int {
 func murmurUpdate(h1 int, k1 int) int {
 	var k1u uint
 	k1u = uint(k1) * c1_32
-	k1u = (k1u << 15) | (k1u >> 17) // rotl32(k1u, 15)
+        k1u = rotateLeft(k1u, 15)
 	k1u *= c2_32
 
 	var h1u = uint(h1) ^ k1u
-	h1u = (h1u << 13) | (h1u >> 19) // rotl32(h1u, 13)
+        k1u = rotateLeft(k1u, 13)
 	h1u = h1u*5 + 0xe6546b64
 	return int(h1u)
 }

From 2d71d943863f13a48acdeb24740e23dddb611734 Mon Sep 17 00:00:00 2001
From: David Sisson <dsisson@google.com>
Date: Wed, 6 Dec 2017 11:04:31 -0800
Subject: [PATCH 2/2] Updated formatting.

---
 runtime/Go/antlr/utils.go | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/runtime/Go/antlr/utils.go b/runtime/Go/antlr/utils.go
index 52d16c759..bba2ffae7 100644
--- a/runtime/Go/antlr/utils.go
+++ b/runtime/Go/antlr/utils.go
@@ -360,24 +360,24 @@ const uintSize = 32 << (^uint(0) >> 32 & 1) // 32 or 64
 // rotateLeft returns the value of x rotated left by (k mod UintSize) bits.
 // To rotate x right by k bits, call RotateLeft(x, -k).
 func rotateLeft(x uint, k int) uint {
-  if uintSize == 32 {
-    return uint(rotateLeft32(uint32(x), k))
-  }
-  return uint(rotateLeft64(uint64(x), k))
+	if uintSize == 32 {
+		return uint(rotateLeft32(uint32(x), k))
+	}
+	return uint(rotateLeft64(uint64(x), k))
 }
 
 // rotateLeft32 returns the value of x rotated left by (k mod 32) bits.
 func rotateLeft32(x uint32, k int) uint32 {
-  const n = 32
-  s := uint(k) & (n - 1)
-  return x<<s | x>>(n-s)
+	const n = 32
+	s := uint(k) & (n - 1)
+	return x<<s | x>>(n-s)
 }
 
 // rotateLeft64 returns the value of x rotated left by (k mod 64) bits.
 func rotateLeft64(x uint64, k int) uint64 {
-  const n = 64
-  s := uint(k) & (n - 1)
-  return x<<s | x>>(n-s)
+	const n = 64
+	s := uint(k) & (n - 1)
+	return x<<s | x>>(n-s)
 }
 
 
@@ -395,11 +395,11 @@ func murmurInit(seed int) int {
 func murmurUpdate(h1 int, k1 int) int {
 	var k1u uint
 	k1u = uint(k1) * c1_32
-        k1u = rotateLeft(k1u, 15)
+	k1u = rotateLeft(k1u, 15)
 	k1u *= c2_32
 
 	var h1u = uint(h1) ^ k1u
-        k1u = rotateLeft(k1u, 13)
+	k1u = rotateLeft(k1u, 13)
 	h1u = h1u*5 + 0xe6546b64
 	return int(h1u)
 }