[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.

3 files changed, 7 insertions, 19 deletions

diff --git a/src/hci/shell.c b/src/hci/shell.c
index 18b1068e9..74787e3c1 100644
--- a/src/hci/shell.c
+++ b/src/hci/shell.c
@@ -29,11 +29,6 @@
  *
  */
 
-static struct command commands[0]
-	__table_start ( struct command, commands );
-static struct command commands_end[0]
-	__table_end ( struct command, commands );
-
 /** The shell prompt string */
 static const char shell_prompt[] = "gPXE> ";
 
@@ -65,7 +60,7 @@ static int help_exec ( int argc __unused, char **argv __unused ) {
 	unsigned int hpos = 0;
 
 	printf ( "\nAvailable commands:\n\n" );
-	for ( command = commands ; command < commands_end ; command++ ) {
+	for_each_table_entry ( command, COMMANDS ) {
 		hpos += printf ( "  %s", command->name );
 		if ( hpos > ( 16 * 4 ) ) {
 			printf ( "\n" );
diff --git a/src/hci/strerror.c b/src/hci/strerror.c
index 74995e8b4..30532b398 100644
--- a/src/hci/strerror.c
+++ b/src/hci/strerror.c
@@ -18,11 +18,6 @@
  *
  */
 
-static struct errortab errortab_start[0]
-	__table_start ( struct errortab, errortab );
-static struct errortab errortab_end[0]
-	__table_end ( struct errortab, errortab );
-
 /**
  * Find error description
  *
@@ -33,8 +28,7 @@ static struct errortab errortab_end[0]
 static struct errortab * find_error ( int errno, int mask ) {
 	struct errortab *errortab;
 
-	for ( errortab = errortab_start ; errortab < errortab_end ;
-	      errortab++ ) {
+	for_each_table_entry ( errortab, ERRORTAB ) {
 		if ( ( ( errortab->errno ^ errno ) & mask ) == 0 )
 			return errortab;
 	}
diff --git a/src/hci/tui/settings_ui.c b/src/hci/tui/settings_ui.c
index 4ab382704..61f94cdea 100644
--- a/src/hci/tui/settings_ui.c
+++ b/src/hci/tui/settings_ui.c
@@ -77,12 +77,8 @@ struct setting_widget {
 	char value[256]; /* enough size for a DHCP string */
 };
 
-/** Registered configuration settings */
-static struct setting all_settings[0]
-	__table_start ( struct setting, settings );
-static struct setting all_settings_end[0]
-	__table_end ( struct setting, settings );
-#define NUM_SETTINGS ( ( unsigned ) ( all_settings_end - all_settings ) )
+/** Number of registered configuration settings */
+#define NUM_SETTINGS table_num_entries ( struct setting, SETTINGS )
 
 static void load_setting ( struct setting_widget *widget ) __nonnull;
 static int save_setting ( struct setting_widget *widget ) __nonnull;
@@ -223,6 +219,9 @@ static int edit_setting ( struct setting_widget *widget, int key ) {
 static void init_setting_index ( struct setting_widget *widget,
 				 struct settings *settings,
 				 unsigned int index ) {
+	struct setting *all_settings =
+		table_start ( struct setting, SETTINGS );
+
 	init_setting ( widget, settings, &all_settings[index],
 		       ( SETTINGS_LIST_ROW + index ), SETTINGS_LIST_COL );
 }