re PR debug/48041 (dwarf2out emits unnecessary null byte in empty .debug_abbrev section)

PR debug/48041
* dwarf2out.c (output_abbrev_section): Only write table when
abbrev_die_table_in_use > 1.

From-SVN: r171441

gcc/ChangeLog

+2011-03-24  Mark Wielaard  <mjw@redhat.com>
+
+	PR debug/48041
+	* dwarf2out.c (output_abbrev_section): Only write table when
+	abbrev_die_table_in_use > 1.
+
 2011-02-24  Richard Henderson  <rth@redhat.com>
 
 	* config/alpha/alpha.c (alpha_expand_unaligned_load): Use extql.

gcc/dwarf2out.c

@@ -11056,6 +11056,9 @@ output_abbrev_section (void)
 {
   unsigned long abbrev_id;
 
+  if (abbrev_die_table_in_use == 1)
+    return;
+
   for (abbrev_id = 1; abbrev_id < abbrev_die_table_in_use; ++abbrev_id)
     {
       dw_die_ref abbrev = abbrev_die_table[abbrev_id];