elide empty .debug_loc

[Richard Henderson]

H.J. reported that an empty .debug_loc crashed the Irix ld.so.
I can't verify that, but it does make sense to not bother to 
emit it if its unused.


r~


        * dwarf2out.c (dwarf2out_init): Don't emit .debug_loc label here.
        (dwarf2out_finish): Do it here.  Emit .debug_loc before .debug_info.

Index: dwarf2out.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/dwarf2out.c,v
retrieving revision 1.303
diff -c -p -d -r1.303 dwarf2out.c
*** dwarf2out.c	2001/08/17 02:33:24	1.303
--- dwarf2out.c	2001/08/17 18:33:29
*************** dwarf2out_init (main_input_filename)
*** 11693,11701 ****
  			       DEBUG_INFO_SECTION_LABEL, 0);
    ASM_GENERATE_INTERNAL_LABEL (debug_line_section_label,
  			       DEBUG_LINE_SECTION_LABEL, 0);
-   ASM_GENERATE_INTERNAL_LABEL (loc_section_label, DEBUG_LOC_SECTION_LABEL, 0);
-   named_section_flags (DEBUG_LOC_SECTION, SECTION_DEBUG);
-   ASM_OUTPUT_LABEL (asm_out_file, loc_section_label);
    named_section_flags (DEBUG_ABBREV_SECTION, SECTION_DEBUG);
    ASM_OUTPUT_LABEL (asm_out_file, abbrev_section_label);
    named_section_flags (DEBUG_INFO_SECTION, SECTION_DEBUG);
--- 11693,11698 ----
*************** dwarf2out_finish (input_filename)
*** 11785,11790 ****
--- 11782,11799 ----
        output_line_info ();
      }
  
+   /* Output location list section if necessary.  */
+   if (have_location_lists)
+     {
+       /* Output the location lists info.  */
+       named_section_flags (DEBUG_LOC_SECTION, SECTION_DEBUG);
+       ASM_GENERATE_INTERNAL_LABEL (loc_section_label,
+ 				   DEBUG_LOC_SECTION_LABEL, 0);
+       ASM_OUTPUT_LABEL (asm_out_file, loc_section_label);
+       output_location_lists (die);
+       have_location_lists = 0;
+     }
+ 
    /* We can only use the low/high_pc attributes if all of the code was
       in .text.  */
    if (separate_line_info_table_in_use == 0)
*************** dwarf2out_finish (input_filename)
*** 11829,11843 ****
        /* Output the address range information.  */
        named_section_flags (DEBUG_ARANGES_SECTION, SECTION_DEBUG);
        output_aranges ();
-     }
- 
-   /* Output location list section if necessary.  */
-   if (have_location_lists)
-     {
-       /* Output the location lists info.  */
-       named_section_flags (DEBUG_LOC_SECTION, SECTION_DEBUG);
-       output_location_lists (die);
-       have_location_lists = 0;
      }
  
    /* Output ranges section if necessary.  */
--- 11838,11843 ----