Use clear on a few more slices.

This is similar to pull request #9749.

PiperOrigin-RevId: 586512951

pkg/abi/linux/netdevice.go

@@ -58,9 +58,7 @@ func (ifr *IFReq) Name() string {
 // SetName sets the name.
 func (ifr *IFReq) SetName(name string) {
 	n := copy(ifr.IFName[:], []byte(name))
-	for i := n; i < len(ifr.IFName); i++ {
-		ifr.IFName[i] = 0
-	}
+	clear(ifr.IFName[n:])
 }
 
 // SizeOfIFReq is the binary size of an IFReq struct (40 bytes).

pkg/buffer/buffer.go

@@ -189,12 +189,9 @@ func (b *Buffer) GrowTo(length int64, zero bool) {
 			sz = int(length - b.size)
 		}
 
-		// Zero the written section; note that this pattern is
-		// specifically recognized and optimized by the compiler.
+		// Zero the written section.
 		if zero {
-			for i := v.write; i < v.write+sz; i++ {
-				v.chunk.data[i] = 0
-			}
+			clear(v.chunk.data[v.write : v.write+sz])
 		}
 
 		// Advance the index.

pkg/coverage/coverage.go

@@ -106,9 +106,7 @@ func ClearCoverageData() {
 	// which would drastically degrade performance. Slight discrepancies due to
 	// racing is okay for the purposes of kcov.
 	for _, counters := range coverdata.Counters {
-		for index := 0; index < len(counters); index++ {
-			counters[index] = 0
-		}
+		clear(counters)
 	}
 }
 

pkg/sentry/kernel/sched/cpuset.go

@@ -88,9 +88,7 @@ func (c *CPUSet) ClearAbove(cpu uint) {
 		return
 	}
 	(*c)[i] &^= 0xff << (cpu % bitsPerByte)
-	for i++; i < c.Size(); i++ {
-		(*c)[i] = 0
-	}
+	clear((*c)[i+1 : c.Size()])
 }
 
 // ForEachCPU iterates over the CPUSet and calls fn with the cpu index if

pkg/tcpip/header/ndp_options.go

@@ -339,8 +339,8 @@ func (b NDPOptions) Serialize(s NDPOptionsSerializer) int {
 		used := o.serializeInto(b[2:])
 
 		// Zero out remaining (padding) bytes, if any exists.
-		for i := used + 2; i < l; i++ {
-			b[i] = 0
+		if used+2 < l {
+			clear(b[used+2 : l])
 		}
 
 		b = b[l:]
@@ -566,9 +566,7 @@ func (o NDPPrefixInformation) serializeInto(b []byte) int {
 
 	// Zero out the Reserved2 field.
 	reserved2 := b[ndpPrefixInformationReserved2Offset:][:ndpPrefixInformationReserved2Length]
-	for i := range reserved2 {
-		reserved2[i] = 0
-	}
+	clear(reserved2)
 
 	return used
 }
@@ -687,9 +685,7 @@ func (o NDPRecursiveDNSServer) serializeInto(b []byte) int {
 	used := copy(b, o)
 
 	// Zero out the reserved bytes that are before the Lifetime field.
-	for i := 0; i < ndpRecursiveDNSServerLifetimeOffset; i++ {
-		b[i] = 0
-	}
+	clear(b[0:ndpRecursiveDNSServerLifetimeOffset])
 
 	return used
 }
@@ -782,9 +778,7 @@ func (o NDPDNSSearchList) serializeInto(b []byte) int {
 	used := copy(b, o)
 
 	// Zero out the reserved bytes that are before the Lifetime field.
-	for i := 0; i < ndpDNSSearchListLifetimeOffset; i++ {
-		b[i] = 0
-	}
+	clear(b[0:ndpDNSSearchListLifetimeOffset])
 
 	return used
 }

pkg/tcpip/stack/stack.go

@@ -964,14 +964,14 @@ func (s *Stack) removeNICLocked(id tcpip.NICID) tcpip.Error {
 	// Remove routes in-place. n tracks the number of routes written.
 	s.routeMu.Lock()
 	n := 0
-	for i, r := range s.routeTable {
-		s.routeTable[i] = tcpip.Route{}
+	for _, r := range s.routeTable {
 		if r.NIC != id {
 			// Keep this route.
 			s.routeTable[n] = r
 			n++
 		}
 	}
+	clear(s.routeTable[n:])
 	s.routeTable = s.routeTable[:n]
 	s.routeMu.Unlock()