Merge commit 'holger/strings'

diff --combined src/include/compiler.h
index 2151fc6,15efb70..a195e53
--- 1/src/include/compiler.h
--- 2/src/include/compiler.h
+++ b/src/include/compiler.h
@@@ -279,6 -279,31 +279,31 @@@ extern void dbg_hex_dump_da ( unsigned 
  /** Apply standard C calling conventions */
  #define __cdecl __attribute__ (( cdecl , regparm(0) ))
  
+ /**
+  * Declare a function as pure - i.e. without side effects
+  */
+ #define __pure __attribute__ (( pure ))
+ 
+ /**
+  * Declare a function as const - i.e. it does not access global memory
+  * (including dereferencing pointers passed to it) at all.
+  * Must also not call any non-const functions.
+  */
+ #define __const __attribute__ (( const ))
+ 
+ /**
+  * Declare a function's pointer parameters as non-null - i.e. force
+  * compiler to check pointers at compile time and enable possible
+  * optimizations based on that fact
+  */
+ #define __nonnull __attribute__ (( nonnull ))
+ 
+ /**
+  * Declare a pointer returned by a function as a unique memory address
+  * as returned by malloc-type functions.
+  */
+ #define __malloc __attribute__ (( malloc ))
+ 
  /**
   * Declare a function as used.
   *
@@@ -311,11 -336,6 +336,11 @@@
   */
  #define __shared __asm__ ( "_shared_bss" )
  
 +/**
 + * Optimisation barrier
 + */
 +#define barrier() __asm__ __volatile__ ( "" : : : "memory" )
 +
  #endif /* ASSEMBLY */
  
  #endif /* COMPILER_H */

diff --combined src/include/gpxe/dhcp.h
index bbd345c,8f5651b..43bccf1
--- 1/src/include/gpxe/dhcp.h
--- 2/src/include/gpxe/dhcp.h
+++ b/src/include/gpxe/dhcp.h
@@@ -168,11 -168,6 +168,11 @@@ struct job_interface
   */
  #define DHCP_EB_SIADDR DHCP_ENCAP_OPT ( DHCP_EB_ENCAP, 3 )
  
 +/*
 + * Tags in the range 0x10-0x7f are reserved for feature markers
 + *
 + */
 +
  /** Network device descriptor
   *
   * Byte 0 is the bus type ID; remaining bytes depend on the bus type.
@@@ -507,7 -502,7 +507,7 @@@ extern void register_dhcp_options ( str
  extern void unregister_dhcp_options ( struct dhcp_option_block *options );
  extern void init_dhcp_options ( struct dhcp_option_block *options,
                                void *data, size_t max_len );
- extern struct dhcp_option_block * alloc_dhcp_options ( size_t max_len );
+ extern struct dhcp_option_block * __malloc alloc_dhcp_options ( size_t max_len );
  extern struct dhcp_option *
  set_dhcp_option ( struct dhcp_option_block *options, unsigned int tag,
                  const void *data, size_t len );

diff --combined src/net/ipv6.c
index a91cb06,c228f09..c07ff94
--- 1/src/net/ipv6.c
--- 2/src/net/ipv6.c
+++ b/src/net/ipv6.c
@@@ -19,7 -19,10 +19,7 @@@ struct net_protocol ipv6_protocol
  
  /* Unspecified IP6 address */
  static struct in6_addr ip6_none = {
 -        .in6_u.u6_addr32[0] = 0,
 -        .in6_u.u6_addr32[1] = 0,
 -        .in6_u.u6_addr32[2] = 0,
 -        .in6_u.u6_addr32[3] = 0,
 +        .in6_u.u6_addr32 = { 0,0,0,0 }
  };
  
  /** An IPv6 routing table entry */
@@@ -52,11 -55,10 +52,10 @@@ static LIST_HEAD ( miniroutes )
   * @v gateway         Gateway address (or ::0 for no gateway)
   * @ret miniroute     Routing table entry, or NULL
   */
- static struct ipv6_miniroute * add_ipv6_miniroute ( struct net_device *netdev,
-                                                   struct in6_addr prefix,
-                                                   int prefix_len,
-                                                   struct in6_addr address,
-                                                   struct in6_addr gateway ) {
+ static struct ipv6_miniroute * __malloc 
+ add_ipv6_miniroute ( struct net_device *netdev, struct in6_addr prefix,
+                    int prefix_len, struct in6_addr address,
+                    struct in6_addr gateway ) {
        struct ipv6_miniroute *miniroute;
        
        miniroute = malloc ( sizeof ( *miniroute ) );