[tables] Redefine methods for accessing linker tables

Intel's C compiler (icc) chokes on the zero-length arrays that we
currently use as part of the mechanism for accessing linker table
entries.  Abstract away the zero-length arrays, to make a port to icc
easier.

Introduce macros such as for_each_table_entry() to simplify the common
case of iterating over all entries in a linker table.

Represent table names as #defined string constants rather than
unquoted literals; this avoids visual confusion between table names
and C variable or type names, and also allows us to force a
compilation error in the event of incorrect table names.

11 files changed, 20 insertions, 108 deletions

diff --git a/src/core/console.c b/src/core/console.c
index c9773f71..1ea3dc13 100644
--- a/src/core/console.c
+++ b/src/core/console.c
@@ -5,11 +5,6 @@
 
 /** @file */
 
-static struct console_driver console_drivers[0]
-	__table_start ( struct console_driver, console );
-static struct console_driver console_drivers_end[0]
-	__table_end ( struct console_driver, console );
-
 /**
  * Write a single character to each console device.
  *
@@ -28,8 +23,7 @@ void putchar ( int character ) {
 	if ( character == '\n' )
 		putchar ( '\r' );
 
-	for ( console = console_drivers; console < console_drivers_end ;
-	      console++ ) {
+	for_each_table_entry ( console, CONSOLES ) {
 		if ( ( ! console->disabled ) && console->putchar )
 			console->putchar ( character );
 	}
@@ -51,8 +45,7 @@ void putchar ( int character ) {
 static struct console_driver * has_input ( void ) {
 	struct console_driver *console;
 
-	for ( console = console_drivers; console < console_drivers_end ;
-	      console++ ) {
+	for_each_table_entry ( console, CONSOLES ) {
 		if ( ( ! console->disabled ) && console->iskey ) {
 			if ( console->iskey () )
 				return console;
diff --git a/src/core/device.c b/src/core/device.c
index 84915c2d..1f57e4c6 100644
--- a/src/core/device.c
+++ b/src/core/device.c
@@ -29,11 +29,6 @@
  *
  */
 
-static struct root_device root_devices[0]
-	__table_start ( struct root_device, root_devices );
-static struct root_device root_devices_end[0]
-	__table_end ( struct root_device, root_devices );
-
 /** Registered root devices */
 static LIST_HEAD ( devices );
 
@@ -77,7 +72,7 @@ static void probe_devices ( void ) {
 	struct root_device *rootdev;
 	int rc;
 
-	for ( rootdev = root_devices; rootdev < root_devices_end; rootdev++ ) {
+	for_each_table_entry ( rootdev, ROOT_DEVICES ) {
 		list_add ( &rootdev->dev.siblings, &devices );
 		INIT_LIST_HEAD ( &rootdev->dev.children );
 		if ( ( rc = rootdev_probe ( rootdev ) ) != 0 )
diff --git a/src/core/exec.c b/src/core/exec.c
index a9861b60..181ca4c5 100644
--- a/src/core/exec.c
+++ b/src/core/exec.c
@@ -34,11 +34,6 @@
  *
  */
 
-static struct command commands[0]
-	__table_start ( struct command, commands );
-static struct command commands_end[0]
-	__table_end ( struct command, commands );
-
 /* Avoid dragging in getopt.o unless a command really uses it */
 int optind;
 int nextchar;
@@ -78,7 +73,7 @@ int execv ( const char *command, char * const argv[] ) {
 	reset_getopt();
 
 	/* Hand off to command implementation */
-	for ( cmd = commands ; cmd < commands_end ; cmd++ ) {
+	for_each_table_entry ( cmd, COMMANDS ) {
 		if ( strcmp ( command, cmd->name ) == 0 )
 			return cmd->exec ( argc, ( char ** ) argv );
 	}
diff --git a/src/core/gdbstub.c b/src/core/gdbstub.c
index bbed344f..45df7f2b 100644
--- a/src/core/gdbstub.c
+++ b/src/core/gdbstub.c
@@ -54,10 +54,6 @@ struct gdbstub {
 	int len;                         /* length of payload */
 };
 
-/* Transports */
-static struct gdb_transport gdb_transport_start[0] __table_start ( struct gdb_transport, gdb_transports );
-static struct gdb_transport gdb_transport_end[0] __table_end ( struct gdb_transport, gdb_transports );
-
 /* Packet parser states */
 static void gdbstub_state_new ( struct gdbstub *stub, char ch );
 static void gdbstub_state_data ( struct gdbstub *stub, char ch );
@@ -387,7 +383,8 @@ void gdbstub_handler ( int signo, gdbreg_t *regs ) {
 
 struct gdb_transport *find_gdb_transport ( const char *name ) {
 	struct gdb_transport *trans;
-	for ( trans = gdb_transport_start; trans < gdb_transport_end; trans++ ) {
+
+	for_each_table_entry ( trans, GDB_TRANSPORTS ) {
 		if ( strcmp ( trans->name, name ) == 0 ) {
 			return trans;
 		}
diff --git a/src/core/image.c b/src/core/image.c
index 277d09a9..0d188c30 100644
--- a/src/core/image.c
+++ b/src/core/image.c
@@ -37,12 +37,6 @@
 /** List of registered images */
 struct list_head images = LIST_HEAD_INIT ( images );
 
-/** List of image types */
-static struct image_type image_types[0]
-	__table_start ( struct image_type, image_types );
-static struct image_type image_types_end[0]
-	__table_end ( struct image_type, image_types );
-
 /**
  * Free executable/loadable image
  *
@@ -219,7 +213,7 @@ int image_autoload ( struct image *image ) {
 		return image_load ( image );
 
 	/* Otherwise probe for a suitable type */
-	for ( type = image_types ; type < image_types_end ; type++ ) {
+	for_each_table_entry ( type, IMAGE_TYPES ) {
 		DBGC ( image, "IMAGE %p trying type %s\n", image, type->name );
 		rc = image_load_type ( image, type );
 		if ( image->type == NULL )
diff --git a/src/core/init.c b/src/core/init.c
index 50e199ce..e1c9dce0 100644
--- a/src/core/init.c
+++ b/src/core/init.c
@@ -25,18 +25,6 @@
  *
  */
 
-/** Registered initialisation functions */
-static struct init_fn init_fns[0]
-	__table_start ( struct init_fn, init_fns );
-static struct init_fn init_fns_end[0]
-	__table_end ( struct init_fn, init_fns );
-
-/** Registered startup/shutdown functions */
-static struct startup_fn startup_fns[0]
-	__table_start ( struct startup_fn, startup_fns );
-static struct startup_fn startup_fns_end[0]
-	__table_end ( struct startup_fn, startup_fns );
-
 /** "startup() has been called" flag */
 static int started = 0;
 
@@ -54,9 +42,8 @@ void initialise ( void ) {
 	struct init_fn *init_fn;
 
 	/* Call registered initialisation functions */
-	for ( init_fn = init_fns ; init_fn < init_fns_end ; init_fn++ ) {
+	for_each_table_entry ( init_fn, INIT_FNS )
 		init_fn->initialise ();
-	}
 }
 
 /**
@@ -73,8 +60,7 @@ void startup ( void ) {
 		return;
 
 	/* Call registered startup functions */
-	for ( startup_fn = startup_fns ; startup_fn < startup_fns_end ;
-	      startup_fn++ ) {
+	for_each_table_entry ( startup_fn, STARTUP_FNS ) {
 		if ( startup_fn->startup )
 			startup_fn->startup();
 	}
@@ -90,7 +76,7 @@ void startup ( void ) {
  * This function reverses the actions of startup(), and leaves gPXE in
  * a state ready to be removed from memory.  You may call startup()
  * again after calling shutdown().
-
+ *
  * Call this function only once, before either exiting main() or
  * starting up a non-returnable image.
  */
@@ -101,8 +87,7 @@ void shutdown ( int flags ) {
 		return;
 
 	/* Call registered shutdown functions (in reverse order) */
-	for ( startup_fn = startup_fns_end - 1 ; startup_fn >= startup_fns ;
-	      startup_fn-- ) {
+	for_each_table_entry_reverse ( startup_fn, STARTUP_FNS ) {
 		if ( startup_fn->shutdown )
 			startup_fn->shutdown ( flags );
 	}
diff --git a/src/core/main.c b/src/core/main.c
index bd2428f0..809d4dcf 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -27,9 +27,6 @@ Literature dealing with the network protocols:
 #define BOLD	"\033[1m"
 #define CYAN	"\033[36m"
 
-static struct feature features[0] __table_start ( struct feature, features );
-static struct feature features_end[0] __table_end ( struct feature, features );
-
 /**
  * Main entry point
  *
@@ -61,7 +58,7 @@ __asmcall int main ( void ) {
 		 NORMAL " -- Open Source Boot Firmware -- "
 		 CYAN "http://etherboot.org" NORMAL "\n"
 		 "Features:" );
-	for ( feature = features ; feature < features_end ; feature++ )
+	for_each_table_entry ( feature, FEATURES )
 		printf ( " %s", feature->name );
 	printf ( "\n" );
 
diff --git a/src/core/open.c b/src/core/open.c
index db8d92e6..89a96d72 100644
--- a/src/core/open.c
+++ b/src/core/open.c
@@ -30,18 +30,6 @@
  *
  */
 
-/** Registered URI openers */
-static struct uri_opener uri_openers[0]
-	__table_start ( struct uri_opener, uri_openers );
-static struct uri_opener uri_openers_end[0]
-	__table_end ( struct uri_opener, uri_openers );
-
-/** Registered socket openers */
-static struct socket_opener socket_openers[0]
-	__table_start ( struct socket_opener, socket_openers );
-static struct socket_opener socket_openers_end[0]
-	__table_end ( struct socket_opener, socket_openers );
-
 /**
  * Open URI
  *
@@ -63,7 +51,7 @@ int xfer_open_uri ( struct xfer_interface *xfer, struct uri *uri ) {
 		return -ENOMEM;
 
 	/* Find opener which supports this URI scheme */
-	for ( opener = uri_openers ; opener < uri_openers_end ; opener++ ) {
+	for_each_table_entry ( opener, URI_OPENERS ) {
 		if ( strcmp ( resolved_uri->scheme, opener->scheme ) == 0 ) {
 			rc = opener->open ( xfer, resolved_uri );
 			goto done;
@@ -121,7 +109,7 @@ int xfer_open_socket ( struct xfer_interface *xfer, int semantics,
 	       socket_semantics_name ( semantics ),
 	       socket_family_name ( peer->sa_family ) );
 
-	for ( opener = socket_openers; opener < socket_openers_end; opener++ ){
+	for_each_table_entry ( opener, SOCKET_OPENERS ) {
 		if ( ( opener->semantics == semantics ) &&
 		     ( opener->family == peer->sa_family ) ) {
 			return opener->open ( xfer, peer, local );
diff --git a/src/core/process.c b/src/core/process.c
index 6a687140..dcae9017 100644
--- a/src/core/process.c
+++ b/src/core/process.c
@@ -31,12 +31,6 @@
 /** Process run queue */
 static LIST_HEAD ( run_queue );
 
-/** Registered permanent processes */
-static struct process processes[0]
-	__table_start ( struct process, processes );
-static struct process processes_end[0]
-	__table_end ( struct process, processes );
-
 /**
  * Add process to process list
  *
@@ -93,9 +87,8 @@ void step ( void ) {
 static void init_processes ( void ) {
 	struct process *process;
 
-	for ( process = processes ; process < processes_end ; process++ ) {
+	for_each_table_entry ( process, PERMANENT_PROCESSES )
 		process_add ( process );
-	}
 }
 
 /** Process initialiser */
diff --git a/src/core/resolv.c b/src/core/resolv.c
index f4a587f1..667f2ded 100644
--- a/src/core/resolv.c
+++ b/src/core/resolv.c
@@ -150,12 +150,6 @@ struct resolver numeric_resolver __resolver ( RESOLV_NUMERIC ) = {
  ***************************************************************************
  */
 
-/** Registered name resolvers */
-static struct resolver resolvers[0]
-	__table_start ( struct resolver, resolvers );
-static struct resolver resolvers_end[0]
-	__table_end ( struct resolver, resolvers );
-
 /** A name resolution multiplexer */
 struct resolv_mux {
 	/** Reference counter */
@@ -223,7 +217,7 @@ static void resolv_mux_done ( struct resolv_interface *resolv,
 
 	/* Attempt next child resolver, if possible */
 	mux->resolver++;
-	if ( mux->resolver >= resolvers_end ) {
+	if ( mux->resolver >= table_end ( struct resolver, RESOLVERS ) ) {
 		DBGC ( mux, "RESOLV %p failed to resolve name\n", mux );
 		goto finished;
 	}
@@ -262,7 +256,7 @@ int resolv ( struct resolv_interface *resolv, const char *name,
 		return -ENOMEM;
 	resolv_init ( &mux->parent, &null_resolv_ops, &mux->refcnt );
 	resolv_init ( &mux->child, &resolv_mux_child_ops, &mux->refcnt );
-	mux->resolver = resolvers;
+	mux->resolver = table_start ( struct resolver, RESOLVERS );
 	memcpy ( &mux->sa, sa, sizeof ( mux->sa ) );
 	memcpy ( mux->name, name, name_len );
 
diff --git a/src/core/settings.c b/src/core/settings.c
index bb5a382b..55f96383 100644
--- a/src/core/settings.c
+++ b/src/core/settings.c
@@ -37,24 +37,6 @@
  *
  */
 
-/** Registered settings */
-static struct setting settings[0]
-	__table_start ( struct setting, settings );
-static struct setting settings_end[0]
-	__table_end ( struct setting, settings );
-
-/** Registered setting types */
-static struct setting_type setting_types[0]
-	__table_start ( struct setting_type, setting_types );
-static struct setting_type setting_types_end[0]
-	__table_end ( struct setting_type, setting_types );
-
-/** Registered settings applicators */
-static struct settings_applicator settings_applicators[0]
-	__table_start ( struct settings_applicator, settings_applicators );
-static struct settings_applicator settings_applicators_end[0]
-	__table_end ( struct settings_applicator, settings_applicators );
-
 /******************************************************************************
  *
  * Registered settings blocks
@@ -229,8 +211,7 @@ static int apply_settings ( void ) {
 	int rc;
 
 	/* Call all settings applicators */
-	for ( applicator = settings_applicators ;
-	      applicator < settings_applicators_end ; applicator++ ) {
+	for_each_table_entry ( applicator, SETTINGS_APPLICATORS ) {
 		if ( ( rc = applicator->apply() ) != 0 ) {
 			DBG ( "Could not apply settings using applicator "
 			      "%p: %s\n", applicator, strerror ( rc ) );
@@ -670,7 +651,7 @@ int storef_setting ( struct settings *settings, struct setting *setting,
 static struct setting * find_setting ( const char *name ) {
 	struct setting *setting;
 
-	for ( setting = settings ; setting < settings_end ; setting++ ) {
+	for_each_table_entry ( setting, SETTINGS ) {
 		if ( strcmp ( name, setting->name ) == 0 )
 			return setting;
 	}
@@ -686,7 +667,7 @@ static struct setting * find_setting ( const char *name ) {
 static struct setting_type * find_setting_type ( const char *name ) {
 	struct setting_type *type;
 
-	for ( type = setting_types ; type < setting_types_end ; type++ ) {
+	for_each_table_entry ( type, SETTING_TYPES ) {
 		if ( strcmp ( name, type->name ) == 0 )
 			return type;
 	}