Re: Handle multiple .debug_info sections

[Cary Coutant <ccoutant at google dot com>]

>        * readelf.c (load_specific_debug_section): New function, from
>        load_debug_section.
>        (load_debug_section): Use load_specific_debug_section.
>        (display_debug_section): Use load_specific_debug_section.  Check for
>        multiple sections with the same name.

I was happy to see this patch -- I had a similar patch already in
progress when you posted this. Since your patch didn't address
objdump.c, I reworked my patch for that file to use the same approach
you did in readelf.c.

(Sorry I've been sitting on this for so long -- I meant to send it a
long time ago and just forgot about it.)

Tested on i686/x86_64 with gcc -feliminate-dwarf2-dups, which also
generates multiple debug_info sections (as comdats), and with the
experimental -gdwarf-4, which puts each type in a separate
.debug_types section.

OK?

-cary


  * objdump.c (load_specific_debug_section): New function, from
    load_debug_section.
    (load_debug_section): Use load_specific_debug_section.
    (dump_dwarf_section): Likewise.


Index: objdump.c
===================================================================
RCS file: /cvs/src/src/binutils/objdump.c,v
retrieving revision 1.154
diff -u -p -r1.154 objdump.c
--- objdump.c	9 Feb 2009 09:14:15 -0000	1.154
+++ objdump.c	20 Feb 2009 20:00:41 -0000
@@ -2122,12 +2122,12 @@ disassemble_data (bfd *abfd)
   free (sorted_syms);
 }
 
-int
-load_debug_section (enum dwarf_section_display_enum debug, void *file)
+static int
+load_specific_debug_section (enum dwarf_section_display_enum debug,
+			     asection *sec, void *file)
 {
   struct dwarf_section *section = &debug_displays [debug].section;
   bfd *abfd = file;
-  asection *sec;
   bfd_boolean ret;
   int section_is_compressed;

@@ -2135,18 +2135,6 @@ load_debug_section (enum dwarf_section_d
   if (section->start != NULL)
     return 1;

-  /* Locate the debug section.  */
-  sec = bfd_get_section_by_name (abfd, section->uncompressed_name);
-  if (sec != NULL)
-    section->name = section->uncompressed_name;
-  else
-    {
-      sec = bfd_get_section_by_name (abfd, section->compressed_name);
-      if (sec != NULL)
-	section->name = section->compressed_name;
-    }
-  if (sec == NULL)
-    return 0;
   section_is_compressed = section->name == section->compressed_name;

   section->address = 0;
@@ -2182,7 +2170,34 @@ load_debug_section (enum dwarf_section_d
       section->size = size;
     }

-  return ret;
+  return 1;
+}
+
+int
+load_debug_section (enum dwarf_section_display_enum debug, void *file)
+{
+  struct dwarf_section *section = &debug_displays [debug].section;
+  bfd *abfd = file;
+  asection *sec;
+
+  /* If it is already loaded, do nothing.  */
+  if (section->start != NULL)
+    return 1;
+
+  /* Locate the debug section.  */
+  sec = bfd_get_section_by_name (abfd, section->uncompressed_name);
+  if (sec != NULL)
+    section->name = section->uncompressed_name;
+  else
+    {
+      sec = bfd_get_section_by_name (abfd, section->compressed_name);
+      if (sec != NULL)
+        section->name = section->compressed_name;
+    }
+  if (sec == NULL)
+    return 0;
+
+  return load_specific_debug_section (debug, sec, file);
 }

 void
@@ -2222,7 +2237,11 @@ dump_dwarf_section (bfd *abfd, asection
 	  {
 	    struct dwarf_section *sec = &debug_displays [i].section;

-	    if (load_debug_section (i, abfd))
+	    if (strcmp (sec->uncompressed_name, match) == 0)
+	      sec->name = sec->uncompressed_name;
+	    else
+	      sec->name = sec->compressed_name;
+	    if (load_specific_debug_section (i, section, abfd))
 	      {
 		debug_displays [i].display (sec, abfd);