optimize 16- and 32-bit moves

function                                             old     new   delta
udhcpd_main                                         1239    1257     +18
udhcp_add_simple_option                               93      92      -1
buffer_read_le_u32                                    19      18      -1
unpack_gz_stream_with_info                           526     520      -6
dnsd_main                                           1470    1463      -7
udhcp_run_script                                    1208    1186     -22
send_ACK                                             255     229     -26
arping_main                                         1661    1623     -38
send_offer                                           470     428     -42
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/8 up/down: 18/-143)          Total: -125 bytes

diff --git a/archival/libunarchive/decompress_unzip.c b/archival/libunarchive/decompress_unzip.c
index e83cd4f45254e20f807899362b33a3d5fcedc4dd..86969251e065fcafeb0aa57668f2b86c1a69f61b 100644 (file)
--- a/archival/libunarchive/decompress_unzip.c
+++ b/archival/libunarchive/decompress_unzip.c
@@ -1083,8 +1083,7 @@ static uint16_t buffer_read_le_u16(STATE_PARAM_ONLY)
 {
        uint16_t res;
 #if BB_LITTLE_ENDIAN
-       /* gcc 4.2.1 is very clever */
-       memcpy(&res, &bytebuffer[bytebuffer_offset], 2);
+       move_from_unaligned16(res, &bytebuffer[bytebuffer_offset]);
 #else
        res = bytebuffer[bytebuffer_offset];
        res |= bytebuffer[bytebuffer_offset + 1] << 8;
@@ -1097,7 +1096,7 @@ static uint32_t buffer_read_le_u32(STATE_PARAM_ONLY)
 {
        uint32_t res;
 #if BB_LITTLE_ENDIAN
-       memcpy(&res, &bytebuffer[bytebuffer_offset], 4);
+       move_from_unaligned32(res, &bytebuffer[bytebuffer_offset]);
 #else
        res = bytebuffer[bytebuffer_offset];
        res |= bytebuffer[bytebuffer_offset + 1] << 8;

diff --git a/include/platform.h b/include/platform.h
index b8c85dba0ddd27afd20bfc77a71b1bf702874078..5d6a181071ebed5df4add7f07253aee515365d91 100644 (file)
--- a/include/platform.h
+++ b/include/platform.h
@@ -151,13 +151,19 @@
 
 /* ---- Unaligned access ------------------------------------ */
 
-/* parameter is supposed to be an uint32_t* ptr */
+/* NB: unaligned parameter should be a pointer, aligned one -
+ * a lvalue. This makes it more likely to not swap them by mistake
+ */
 #if defined(i386) || defined(__x86_64__)
-#define get_unaligned_u32p(u32p) (*(u32p))
+#define move_from_unaligned16(v, u16p) ((v) = *(uint16_t*)(u16p))
+#define move_from_unaligned32(v, u32p) ((v) = *(uint32_t*)(u32p))
+#define move_to_unaligned32(u32p, v)   (*(uint32_t*)(u32p) = (v))
 /* #elif ... - add your favorite arch today! */
 #else
 /* performs reasonably well (gcc usually inlines memcpy here) */
-#define get_unaligned_u32p(u32p) ({ uint32_t __t; memcpy(&__t, (u32p), 4); __t; })
+#define move_from_unaligned16(v, u16p) (memcpy(&(v), (u16p), 2))
+#define move_from_unaligned32(v, u32p) (memcpy(&(v), (u32p), 4))
+#define move_to_unaligned32(u32p, v)   (memcpy((u32p), &(v), 4))
 #endif
 
 /* ---- Networking ------------------------------------------ */

diff --git a/networking/arping.c b/networking/arping.c
index e4429973b3c70163003201b4c3d189339d526a1b..e7b842f5b89fb3faf30259708df25c88c450b54a 100644 (file)
--- a/networking/arping.c
+++ b/networking/arping.c
@@ -153,6 +153,15 @@ static bool recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
        struct arphdr *ah = (struct arphdr *) buf;
        unsigned char *p = (unsigned char *) (ah + 1);
        struct in_addr src_ip, dst_ip;
+       /* moves below assume in_addr is 4 bytes big, ensure that */
+       struct BUG_in_addr_must_be_4 {
+               char BUG_in_addr_must_be_4[
+                       sizeof(struct in_addr) == 4 ? 1 : -1
+               ];
+               char BUG_s_addr_must_be_4[
+                       sizeof(src_ip.s_addr) == 4 ? 1 : -1
+               ];
+       };
 
        /* Filter out wild packets */
        if (FROM->sll_pkttype != PACKET_HOST
@@ -171,13 +180,13 @@ static bool recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
 
        /* Protocol must be IP. */
        if (ah->ar_pro != htons(ETH_P_IP)
-               || (ah->ar_pln != 4)
-               || (ah->ar_hln != me.sll_halen)
-               || (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln))))
+        || (ah->ar_pln != 4)
+        || (ah->ar_hln != me.sll_halen)
+        || (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln))))
                return false;
 
-       memcpy(&src_ip, p + ah->ar_hln, 4);
-       memcpy(&dst_ip, p + ah->ar_hln + 4 + ah->ar_hln, 4);
+       move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln);
+       move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln);
 
        if (dst.s_addr != src_ip.s_addr)
                return false;
@@ -200,7 +209,7 @@ static bool recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
                   dst_ip/dst_hw do not matter.
                 */
                if ((memcmp(p, &me.sll_addr, me.sll_halen) == 0)
-                       || (src.s_addr && src.s_addr != dst_ip.s_addr))
+                || (src.s_addr && src.s_addr != dst_ip.s_addr))
                        return false;
        }
        if (!(option_mask32 & QUIET)) {
@@ -306,7 +315,7 @@ int arping_main(int argc UNUSED_PARAM, char **argv)
        /* if (!inet_aton(target, &dst)) - not needed */ {
                len_and_sockaddr *lsa;
                lsa = xhost_and_af2sockaddr(target, 0, AF_INET);
-               memcpy(&dst, &lsa->u.sin.sin_addr.s_addr, 4);
+               dst = lsa->u.sin.sin_addr;
                if (ENABLE_FEATURE_CLEAN_UP)
                        free(lsa);
        }

diff --git a/networking/dnsd.c b/networking/dnsd.c
index e8dcb404b059a75a90c093affcff4516e01b0b37..434903fe1b5fb8bd743cc7d940e7c2b21b319a39 100644 (file)
--- a/networking/dnsd.c
+++ b/networking/dnsd.c
@@ -253,7 +253,7 @@ static int process_packet(uint8_t *buf)
                        goto empty_packet;
                }
                v32 = a.s_addr; /* in case long != int */
-               memcpy(answstr, &v32, 4);
+               move_to_unaligned32(answstr, v32);
                outr_rlen = 4;                  // uint32_t IP
        } else
                outr_rlen = strlen((char *)answstr) + 1;        // a host name

diff --git a/networking/libiproute/libnetlink.c b/networking/libiproute/libnetlink.c
index 01454fbf576056a2ad534d846bcf0767b11f8537..6d51d8deba9e182b16a25e07a3e8a226130bf43a 100644 (file)
--- a/networking/libiproute/libnetlink.c
+++ b/networking/libiproute/libnetlink.c
@@ -341,7 +341,7 @@ int FAST_FUNC addattr32(struct nlmsghdr *n, int maxlen, int type, uint32_t data)
        rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
        rta->rta_type = type;
        rta->rta_len = len;
-       memcpy(RTA_DATA(rta), &data, 4);
+       move_to_unaligned32(RTA_DATA(rta), data);
        n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
        return 0;
 }
@@ -372,7 +372,7 @@ int FAST_FUNC rta_addattr32(struct rtattr *rta, int maxlen, int type, uint32_t d
        subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
        subrta->rta_type = type;
        subrta->rta_len = len;
-       memcpy(RTA_DATA(subrta), &data, 4);
+       move_to_unaligned32(RTA_DATA(subrta), data);
        rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
        return 0;
 }

diff --git a/networking/libiproute/ll_addr.c b/networking/libiproute/ll_addr.c
index e732efdb2c55902e72e8b8dd9e5d3b6369e56c2e..f50e3719338e89e6a42ea11d80809be8c07382fa 100644 (file)
--- a/networking/libiproute/ll_addr.c
+++ b/networking/libiproute/ll_addr.c
@@ -43,6 +43,8 @@ const char *ll_addr_n2a(unsigned char *addr, int alen, int type, char *buf, int
 
 int ll_addr_a2n(unsigned char *lladdr, int len, char *arg)
 {
+       int i;
+
        if (strchr(arg, '.')) {
                inet_prefix pfx;
                if (get_addr_1(&pfx, arg, AF_INET)) {
@@ -54,26 +56,24 @@ int ll_addr_a2n(unsigned char *lladdr, int len, char *arg)
                }
                memcpy(lladdr, pfx.data, 4);
                return 4;
-       } else {
-               int i;
+       }
 
-               for (i=0; i<len; i++) {
-                       int temp;
-                       char *cp = strchr(arg, ':');
-                       if (cp) {
-                               *cp = 0;
-                               cp++;
-                       }
-                       if (sscanf(arg, "%x", &temp) != 1 || (temp < 0 || temp > 255)) {
-                               bb_error_msg("\"%s\" is invalid lladdr", arg);
-                               return -1;
-                       }
-                       lladdr[i] = temp;
-                       if (!cp) {
-                               break;
-                       }
-                       arg = cp;
+       for (i = 0; i < len; i++) {
+               int temp;
+               char *cp = strchr(arg, ':');
+               if (cp) {
+                       *cp = 0;
+                       cp++;
+               }
+               if (sscanf(arg, "%x", &temp) != 1 || (temp < 0 || temp > 255)) {
+                       bb_error_msg("\"%s\" is invalid lladdr", arg);
+                       return -1;
+               }
+               lladdr[i] = temp;
+               if (!cp) {
+                       break;
                }
-               return i+1;
+               arg = cp;
        }
+       return i+1;
 }

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index 2d48980d9d9007578cb120f8126695a18a1f5754..e2e5b0a82382f2939e2ad1fbd0a8369004eba2e2 100644 (file)
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -503,7 +503,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                                /* still selecting - this server looks bad */
                                        }
                                        /* it IS unaligned sometimes, don't "optimize" */
-                                       server_addr = get_unaligned_u32p((uint32_t*)temp);
+                                       move_from_unaligned32(server_addr, temp);
                                        xid = packet.xid;
                                        requested_ip = packet.yiaddr;
 
@@ -525,7 +525,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                                lease_seconds = 60 * 60;
                                        } else {
                                                /* it IS unaligned sometimes, don't "optimize" */
-                                               lease_seconds = get_unaligned_u32p((uint32_t*)temp);
+                                               move_from_unaligned32(lease_seconds, temp);
                                                lease_seconds = ntohl(lease_seconds);
                                                lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */
                                                if (lease_seconds < 10) /* and not too small */

diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c
index b512c45ee3a9e7fccfb8e572edc4f5db3f9217fe..7b4596895ce97b82e96e74a54db67011becdc8b9 100644 (file)
--- a/networking/udhcp/dhcpd.c
+++ b/networking/udhcp/dhcpd.c
@@ -30,7 +30,9 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
        int server_socket = -1, bytes, retval, max_sock;
        struct dhcpMessage packet;
        uint8_t *state, *server_id, *requested;
-       uint32_t server_id_align, requested_align, static_lease_ip;
+       uint32_t server_id_aligned = server_id_aligned; /* for compiler */
+       uint32_t requested_aligned = requested_aligned;
+       uint32_t static_lease_ip;
        unsigned timeout_end;
        unsigned num_ips;
        unsigned opt;
@@ -79,7 +81,7 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
        option = find_option(server_config.options, DHCP_LEASE_TIME);
        server_config.lease = LEASE_TIME;
        if (option) {
-               memcpy(&server_config.lease, option->data + 2, 4);
+               move_from_unaligned32(server_config.lease, option->data + 2);
                server_config.lease = ntohl(server_config.lease);
        }
 
@@ -190,21 +192,24 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
                        requested = get_option(&packet, DHCP_REQUESTED_IP);
                        server_id = get_option(&packet, DHCP_SERVER_ID);
 
-                       if (requested) memcpy(&requested_align, requested, 4);
-                       if (server_id) memcpy(&server_id_align, server_id, 4);
+                       if (requested)
+                               move_from_unaligned32(requested_aligned, requested);
+                       if (server_id)
+                               move_from_unaligned32(server_id_aligned, server_id);
 
                        if (lease) {
                                if (server_id) {
                                        /* SELECTING State */
-                                       DEBUG("server_id = %08x", ntohl(server_id_align));
-                                       if (server_id_align == server_config.server && requested
-                                        && requested_align == lease->yiaddr
+                                       DEBUG("server_id = %08x", ntohl(server_id_aligned));
+                                       if (server_id_aligned == server_config.server
+                                        && requested
+                                        && requested_aligned == lease->yiaddr
                                        ) {
                                                send_ACK(&packet, lease->yiaddr);
                                        }
                                } else if (requested) {
                                        /* INIT-REBOOT State */
-                                       if (lease->yiaddr == requested_align)
+                                       if (lease->yiaddr == requested_aligned)
                                                send_ACK(&packet, lease->yiaddr);
                                        else
                                                send_NAK(&packet);
@@ -221,7 +226,7 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
 
                        } else if (requested) {
                                /* INIT-REBOOT State */
-                               lease = find_lease_by_yiaddr(requested_align);
+                               lease = find_lease_by_yiaddr(requested_aligned);
                                if (lease) {
                                        if (lease_expired(lease)) {
                                                /* probably best if we drop this lease */
@@ -230,7 +235,7 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
                                        } else
                                                send_NAK(&packet);
                                } else {
-                                       uint32_t r = ntohl(requested_align);
+                                       uint32_t r = ntohl(requested_aligned);
                                        if (r < server_config.start_ip
                                         || r > server_config.end_ip
                                        ) {

diff --git a/networking/udhcp/options.c b/networking/udhcp/options.c
index 2c27e7033c16757219efd43b48a234bf6cf40b12..581a7b67134f7efcafd2a21c249d32921bc269d0 100644 (file)
--- a/networking/udhcp/options.c
+++ b/networking/udhcp/options.c
@@ -224,9 +224,8 @@ int FAST_FUNC add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data)
                        option[OPT_LEN] = len;
                        if (BB_BIG_ENDIAN)
                                data <<= 8 * (4 - len);
-                       /* This memcpy is for processors which can't
-                        * handle a simple unaligned 32-bit assignment */
-                       memcpy(&option[OPT_DATA], &data, 4);
+                       /* Assignment is unaligned! */
+                       move_to_unaligned32(&option[OPT_DATA], data);
                        return add_option_string(optionptr, option);
                }
        }

diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c
index 8dff9b700887173d90e8e070daf8dff27d5b6656..4ae17fb8dd0778bf16b8698177a08cc71f9a415f 100644 (file)
--- a/networking/udhcp/script.c
+++ b/networking/udhcp/script.c
@@ -90,19 +90,19 @@ static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p,
                        dest += sprintf(dest, "%u", *option);
                        break;
                case OPTION_U16:
-                       memcpy(&val_u16, option, 2);
+                       move_from_unaligned16(val_u16, option);
                        dest += sprintf(dest, "%u", ntohs(val_u16));
                        break;
                case OPTION_S16:
-                       memcpy(&val_s16, option, 2);
+                       move_from_unaligned16(val_s16, option);
                        dest += sprintf(dest, "%d", ntohs(val_s16));
                        break;
                case OPTION_U32:
-                       memcpy(&val_u32, option, 4);
+                       move_from_unaligned32(val_u32, option);
                        dest += sprintf(dest, "%lu", (unsigned long) ntohl(val_u32));
                        break;
                case OPTION_S32:
-                       memcpy(&val_s32, option, 4);
+                       move_from_unaligned32(val_s32, option);
                        dest += sprintf(dest, "%ld", (long) ntohl(val_s32));
                        break;
                case OPTION_STRING:
@@ -183,7 +183,7 @@ static char **fill_envp(struct dhcpMessage *packet)
                /* Fill in a subnet bits option for things like /24 */
                if (dhcp_options[i].code == DHCP_SUBNET) {
                        uint32_t subnet;
-                       memcpy(&subnet, temp, 4);
+                       move_from_unaligned32(subnet, temp);
                        envp[j++] = xasprintf("mask=%d", mton(subnet));
                }
  next:

diff --git a/networking/udhcp/serverpacket.c b/networking/udhcp/serverpacket.c
index dcc234c7d1a2668fe1c9d81236c0bd3f00ce5fa0..fca685dd12cb5e55f78b28a37d55cfd38dcec66d 100644 (file)
--- a/networking/udhcp/serverpacket.c
+++ b/networking/udhcp/serverpacket.c
@@ -103,7 +103,8 @@ int FAST_FUNC send_offer(struct dhcpMessage *oldpacket)
 {
        struct dhcpMessage packet;
        struct dhcpOfferedAddr *lease = NULL;
-       uint32_t req_align, lease_time_align = server_config.lease;
+       uint32_t req_align;
+       uint32_t lease_time_aligned = server_config.lease;
        uint8_t *req, *lease_time;
        struct option_set *curr;
        struct in_addr addr;
@@ -120,7 +121,7 @@ int FAST_FUNC send_offer(struct dhcpMessage *oldpacket)
                lease = find_lease_by_chaddr(oldpacket->chaddr);
                if (lease) {
                        if (!lease_expired(lease))
-                               lease_time_align = lease->expires - time(0);
+                               lease_time_aligned = lease->expires - time(0);
                        packet.yiaddr = lease->yiaddr;
                /* Or the client has a requested ip */
                } else if ((req = get_option(oldpacket, DHCP_REQUESTED_IP))
@@ -155,22 +156,22 @@ int FAST_FUNC send_offer(struct dhcpMessage *oldpacket)
                }
                lease_time = get_option(oldpacket, DHCP_LEASE_TIME);
                if (lease_time) {
-                       memcpy(&lease_time_align, lease_time, 4);
-                       lease_time_align = ntohl(lease_time_align);
-                       if (lease_time_align > server_config.lease)
-                               lease_time_align = server_config.lease;
+                       move_from_unaligned32(lease_time_aligned, lease_time);
+                       lease_time_aligned = ntohl(lease_time_aligned);
+                       if (lease_time_aligned > server_config.lease)
+                               lease_time_aligned = server_config.lease;
                }
 
                /* Make sure we aren't just using the lease time from the previous offer */
-               if (lease_time_align < server_config.min_lease)
-                       lease_time_align = server_config.lease;
+               if (lease_time_aligned < server_config.min_lease)
+                       lease_time_aligned = server_config.lease;
                /* ADDME: end of short circuit */
        } else {
                /* It is a static lease... use it */
                packet.yiaddr = static_lease_ip;
        }
 
-       add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_align));
+       add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_aligned));
 
        curr = server_config.options;
        while (curr) {
@@ -203,7 +204,7 @@ int FAST_FUNC send_ACK(struct dhcpMessage *oldpacket, uint32_t yiaddr)
        struct dhcpMessage packet;
        struct option_set *curr;
        uint8_t *lease_time;
-       uint32_t lease_time_align = server_config.lease;
+       uint32_t lease_time_aligned = server_config.lease;
        struct in_addr addr;
 
        init_packet(&packet, oldpacket, DHCPACK);
@@ -211,15 +212,15 @@ int FAST_FUNC send_ACK(struct dhcpMessage *oldpacket, uint32_t yiaddr)
 
        lease_time = get_option(oldpacket, DHCP_LEASE_TIME);
        if (lease_time) {
-               memcpy(&lease_time_align, lease_time, 4);
-               lease_time_align = ntohl(lease_time_align);
-               if (lease_time_align > server_config.lease)
-                       lease_time_align = server_config.lease;
-               else if (lease_time_align < server_config.min_lease)
-                       lease_time_align = server_config.lease;
+               move_from_unaligned32(lease_time_aligned, lease_time);
+               lease_time_aligned = ntohl(lease_time_aligned);
+               if (lease_time_aligned > server_config.lease)
+                       lease_time_aligned = server_config.lease;
+               else if (lease_time_aligned < server_config.min_lease)
+                       lease_time_aligned = server_config.lease;
        }
 
-       add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_align));
+       add_simple_option(packet.options, DHCP_LEASE_TIME, htonl(lease_time_aligned));
 
        curr = server_config.options;
        while (curr) {
@@ -236,7 +237,7 @@ int FAST_FUNC send_ACK(struct dhcpMessage *oldpacket, uint32_t yiaddr)
        if (send_packet(&packet, 0) < 0)
                return -1;
 
-       add_lease(packet.chaddr, packet.yiaddr, lease_time_align);
+       add_lease(packet.chaddr, packet.yiaddr, lease_time_aligned);
        if (ENABLE_FEATURE_UDHCPD_WRITE_LEASES_EARLY) {
                /* rewrite the file with leases at every new acceptance */
                write_leases();

diff --git a/networking/zcip.c b/networking/zcip.c
index 3a349a5afd4b1151d5269a50f88261076d88e3cd..df4c0ec2def3cebf04070eba736b06f50be3f97e 100644 (file)
--- a/networking/zcip.c
+++ b/networking/zcip.c
@@ -279,7 +279,8 @@ int zcip_main(int argc, char **argv)
        // NOTE: the sequence of addresses we try changes only
        // depending on when we detect conflicts.
        {
-               uint32_t t = get_unaligned_u32p((uint32_t *) ((char *)&eth_addr + 2));
+               uint32_t t;
+               move_from_unaligned32(t, ((char *)&eth_addr + 2));
                srand(t);
        }
        if (ip.s_addr == 0)

diff --git a/util-linux/volume_id/linux_raid.c b/util-linux/volume_id/linux_raid.c
index a1130606f5d0128ccef9771249c059a5329bdf68..0877b8ad2dedd1a982a99666c473a4399ab80c15 100644 (file)
--- a/util-linux/volume_id/linux_raid.c
+++ b/util-linux/volume_id/linux_raid.c
@@ -62,7 +62,7 @@ int volume_id_probe_linux_raid(struct volume_id *id, uint64_t off, uint64_t size
        if (mdp->md_magic != cpu_to_le32(MD_MAGIC))
                return -1;
 
-       memcpy(uuid, &mdp->set_uuid0, 4);
+       *(uint32_t*)uuid = mdp->set_uuid0;
        memcpy(&uuid[4], &mdp->set_uuid1, 12);
        volume_id_set_uuid(id, uuid, UUID_DCE);