remove unused labels

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/4274052

11 files changed, 177 insertions, 53 deletions

diff --git a/src/pkg/net/ip.go b/src/pkg/net/ip.go
index e82224a283..1904af0d6a 100644
--- a/src/pkg/net/ip.go
+++ b/src/pkg/net/ip.go
@@ -12,6 +12,8 @@
 
 package net
 
+import "os"
+
 // IP address lengths (bytes).
 const (
 	IPv4len = 4
@@ -39,11 +41,7 @@ type IPMask []byte
 // IPv4 address a.b.c.d.
 func IPv4(a, b, c, d byte) IP {
 	p := make(IP, IPv6len)
-	for i := 0; i < 10; i++ {
-		p[i] = 0
-	}
-	p[10] = 0xff
-	p[11] = 0xff
+	copy(p, v4InV6Prefix)
 	p[12] = a
 	p[13] = b
 	p[14] = c
@@ -51,6 +49,8 @@ func IPv4(a, b, c, d byte) IP {
 	return p
 }
 
+var v4InV6Prefix = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff}
+
 // IPv4Mask returns the IP mask (in 16-byte form) of the
 // IPv4 mask a.b.c.d.
 func IPv4Mask(a, b, c, d byte) IPMask {
@@ -140,9 +140,24 @@ func (ip IP) DefaultMask() IPMask {
 	return nil // not reached
 }
 
+func allFF(b []byte) bool {
+	for _, c := range b {
+		if c != 0xff {
+			return false
+		}
+	}
+	return true
+}
+
 // Mask returns the result of masking the IP address ip with mask.
 func (ip IP) Mask(mask IPMask) IP {
 	n := len(ip)
+	if len(mask) == 16 && len(ip) == 4 && allFF(mask[:12]) {
+		mask = mask[12:]
+	}
+	if len(mask) == 4 && len(ip) == 16 && bytesEqual(ip[:12], v4InV6Prefix) {
+		ip = ip[12:]
+	}
 	if n != len(mask) {
 		return nil
 	}
@@ -245,6 +260,34 @@ func (ip IP) String() string {
 	return s
 }
 
+// Equal returns true if ip and x are the same IP address.
+// An IPv4 address and that same address in IPv6 form are
+// considered to be equal.
+func (ip IP) Equal(x IP) bool {
+	if len(ip) == len(x) {
+		return bytesEqual(ip, x)
+	}
+	if len(ip) == 4 && len(x) == 16 {
+		return bytesEqual(x[0:12], v4InV6Prefix) && bytesEqual(ip, x[12:])
+	}
+	if len(ip) == 16 && len(x) == 4 {
+		return bytesEqual(ip[0:12], v4InV6Prefix) && bytesEqual(ip[12:], x)
+	}
+	return false
+}
+
+func bytesEqual(x, y []byte) bool {
+	if len(x) != len(y) {
+		return false
+	}
+	for i, b := range x {
+		if y[i] != b {
+			return false
+		}
+	}
+	return true
+}
+
 // If mask is a sequence of 1 bits followed by 0 bits,
 // return the number of 1 bits.
 func simpleMaskLength(mask IPMask) int {
@@ -351,7 +394,6 @@ func parseIPv6(s string) IP {
 
 	// Loop, parsing hex numbers followed by colon.
 	j := 0
-L:
 	for j < IPv6len {
 		// Hex number.
 		n, i1, ok := xtoi(s, i)
@@ -432,15 +474,66 @@ L:
 	return p
 }
 
+// A SyntaxError represents a malformed text string and the type of string that was expected.
+type SyntaxError struct {
+	Type string
+	Text string
+}
+
+func (e *SyntaxError) String() string {
+	return "invalid " + e.Type + ": " + e.Text
+}
+
+func parseIP(s string) IP {
+	if p := parseIPv4(s); p != nil {
+		return p
+	}
+	if p := parseIPv6(s); p != nil {
+		return p
+	}
+	return nil
+}
+
 // ParseIP parses s as an IP address, returning the result.
 // The string s can be in dotted decimal ("74.125.19.99")
 // or IPv6 ("2001:4860:0:2001::68") form.
 // If s is not a valid textual representation of an IP address,
 // ParseIP returns nil.
 func ParseIP(s string) IP {
-	p := parseIPv4(s)
-	if p != nil {
+	if p := parseIPv4(s); p != nil {
 		return p
 	}
 	return parseIPv6(s)
 }
+
+// ParseCIDR parses s as a CIDR notation IP address and mask,
+// like "192.168.100.1/24" or "2001:DB8::/48".
+func ParseCIDR(s string) (ip IP, mask IPMask, err os.Error) {
+	i := byteIndex(s, '/')
+	if i < 0 {
+		return nil, nil, &SyntaxError{"CIDR address", s}
+	}
+	ipstr, maskstr := s[:i], s[i+1:]
+	ip = ParseIP(ipstr)
+	nn, i, ok := dtoi(maskstr, 0)
+	if ip == nil || !ok || i != len(maskstr) || nn < 0 || nn > 8*len(ip) {
+		return nil, nil, &SyntaxError{"CIDR address", s}
+	}
+	n := uint(nn)
+	if len(ip) == 4 {
+		v4mask := ^uint32(0xffffffff >> n)
+		mask = IPMask(IPv4(byte(v4mask>>24), byte(v4mask>>16), byte(v4mask>>8), byte(v4mask)))
+		return ip, mask, nil
+	}
+	mask = make(IPMask, 16)
+	for i := 0; i < 16; i++ {
+		if n >= 8 {
+			mask[i] = 0xff
+			n -= 8
+			continue
+		}
+		mask[i] = ^byte(0xff >> n)
+		n = 0
+	}
+	return ip, mask, nil
+}
diff --git a/src/pkg/template/template.go b/src/pkg/template/template.go
index f27c987abe..ba06de4e3a 100644
--- a/src/pkg/template/template.go
+++ b/src/pkg/template/template.go
@@ -267,7 +267,6 @@ func (t *Template) nextItem() []byte {
 	}
 	leadingSpace := i > start
 	// What's left is nothing, newline, delimited string, or plain text
-Switch:
 	switch {
 	case i == len(t.buf):
 		// EOF; nothing to do
diff --git a/src/pkg/xml/xml.go b/src/pkg/xml/xml.go
index 691c13a118..f92abe8256 100644
--- a/src/pkg/xml/xml.go
+++ b/src/pkg/xml/xml.go
@@ -815,7 +815,6 @@ Input:
 			// Parsers are required to recognize lt, gt, amp, apos, and quot
 			// even if they have not been declared.  That's all we allow.
 			var i int
-		CharLoop:
 			for i = 0; i < len(p.tmp); i++ {
 				var ok bool
 				p.tmp[i], ok = p.getc()
diff --git a/test/fixedbugs/bug055.go b/test/fixedbugs/bug055.go
index 0326d828f2..8617396109 100644
--- a/test/fixedbugs/bug055.go
+++ b/test/fixedbugs/bug055.go
@@ -7,16 +7,21 @@
 package main
 
 func main() {
-	var i int;
-	var j int;
-	if true {}
-	{ return }
-	i = 0;
-	if true {} else i++;
-	type s struct {};
-	i = 0;
-	type s2 int;
-	var k = func (a int) int { return a+1 }(3);
-	_, _ = j, k;
-ro: ;
+	var i int
+	var j int
+	if true {
+	}
+	{
+		return
+	}
+	i = 0
+	if true {
+	} else {
+		i++
+	}
+	type s struct{}
+	i = 0
+	type s2 int
+	var k = func(a int) int { return a + 1 }(3)
+	_, _ = j, k
 }
diff --git a/test/fixedbugs/bug076.go b/test/fixedbugs/bug076.go
index 065cecc015..2ca518d76d 100644
--- a/test/fixedbugs/bug076.go
+++ b/test/fixedbugs/bug076.go
@@ -1,4 +1,4 @@
-// $G $D/$F.go && $L $F.$A && ./$A.out
+// $G $D/$F.go && $L $F.$A
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -7,12 +7,16 @@
 package main
 
 func f() {
-exit: ;
+exit:
+	;
+	goto exit
 }
 
 
 func main() {
-exit: ; // this should be legal (labels not properly scoped?)
+exit:
+	; // this should be legal (labels not properly scoped?)
+	goto exit
 }
 
 /*
diff --git a/test/fixedbugs/bug077.go b/test/fixedbugs/bug077.go
index 08028ab10f..2cbf96d98f 100644
--- a/test/fixedbugs/bug077.go
+++ b/test/fixedbugs/bug077.go
@@ -7,7 +7,8 @@
 package main
 
 func main() {
-	var exit int;
+	var exit int
 exit:
-	_ = exit;
+	_ = exit
+	goto exit
 }
diff --git a/test/fixedbugs/bug091.go b/test/fixedbugs/bug091.go
index cfbb09cd82..c2ede7153c 100644
--- a/test/fixedbugs/bug091.go
+++ b/test/fixedbugs/bug091.go
@@ -7,18 +7,19 @@
 package main
 
 func f1() {
-	exit:
-		print("hi\n");
+exit:
+	print("hi\n")
+	goto exit
 }
 
 func f2() {
-	const c = 1234;
+	const c = 1234
 }
 
 func f3() {
-	i := c;	// ERROR "undef"
+	i := c // ERROR "undef"
 }
 
 func main() {
-	f3();
+	f3()
 }
diff --git a/test/fixedbugs/bug137.go b/test/fixedbugs/bug137.go
index 1527924116..9d43f431be 100644
--- a/test/fixedbugs/bug137.go
+++ b/test/fixedbugs/bug137.go
@@ -8,16 +8,21 @@ package main
 
 func main() {
 L1:
-L2:	for i := 0; i < 10; i++ {
-		print(i);
-		break L2;
+L2:
+	for i := 0; i < 10; i++ {
+		print(i)
+		break L2
 	}
 
-L3: ;
-L4:	for i := 0; i < 10; i++ {
-		print(i);
-		break L4;
+L3:
+	;
+L4:
+	for i := 0; i < 10; i++ {
+		print(i)
+		break L4
 	}
+	goto L1
+	goto L3
 }
 
 /*
diff --git a/test/fixedbugs/bug140.go b/test/fixedbugs/bug140.go
index 298081663b..e27b370e76 100644
--- a/test/fixedbugs/bug140.go
+++ b/test/fixedbugs/bug140.go
@@ -7,8 +7,17 @@
 package main
 
 func main() {
-	if true {} else L1: ;
-	if true {} else L2: main() ;
+	if true {
+	} else {
+	L1:
+	}
+	if true {
+	} else {
+	L2:
+		main()
+	}
+	goto L1
+	goto L2
 }
 
 /*
diff --git a/test/fixedbugs/bug178.go b/test/fixedbugs/bug178.go
index 4f586342b4..2059610244 100644
--- a/test/fixedbugs/bug178.go
+++ b/test/fixedbugs/bug178.go
@@ -9,19 +9,25 @@ package main
 func main() {
 L:
 	for i := 0; i < 1; i++ {
-L1:
+	L1:
 		for {
-			break L;
+			break L
 		}
-		panic("BUG: not reached - break");
+		panic("BUG: not reached - break")
 	}
 
 L2:
 	for i := 0; i < 1; i++ {
-L3:
+	L3:
 		for {
-			continue L2;
+			continue L2
 		}
-		panic("BUG: not reached - continue");
+		panic("BUG: not reached - continue")
+	}
+	if false {
+		goto L1
+	}
+	if false {
+		goto L3
 	}
 }
diff --git a/test/fixedbugs/bug179.go b/test/fixedbugs/bug179.go
index 67548733ce..3347613d8d 100644
--- a/test/fixedbugs/bug179.go
+++ b/test/fixedbugs/bug179.go
@@ -10,16 +10,18 @@ func main() {
 L:
 	for {
 		for {
-			break L2;	// ERROR "L2"
-			continue L2;	// ERROR "L2"
+			break L2    // ERROR "L2"
+			continue L2 // ERROR "L2"
 		}
 	}
 
 L1:
-	x := 1;
-	_ = x;
+	x := 1
+	_ = x
 	for {
-		break L1;	// ERROR "L1"
-		continue L1;	// ERROR "L1"
+		break L1    // ERROR "L1"
+		continue L1 // ERROR "L1"
 	}
+
+	goto L
 }