[comitted]: readelf - do not dump NOBITS debug sections

[Nick Clifton <nickc at redhat dot com>]

Hi Guys,

  I am applying the attached patch to fix a problem I encountered
  whilst investigating a gcc debug info generation problem.  Readelf
  was displaying a .eh_frame section as if it contained corrupt data,
  when in fact there was no reliable data there at all.  What had
  happened was that a debug-info-only file had been created by running
  "strip --only-keep-debug" on an executable, but this also preserved
  the non-debug sections, just changing their type to NOBITS.  When
  readelf was then run on the debug-info-only file it dumped the
  .eh_frame section as if it contained real data.

  Tested with no regression on a multitude of toolchains.

Cheers
  Nick

readelf/ChangeLog
2009-05-28  Nick Clifton  <nickc@redhat.com>

	* readelf.c (display_debug_section): Do not display debug sections
	with the NOBITS section type.

Index: binutils/readelf.c
===================================================================
RCS file: /cvs/src/src/binutils/readelf.c,v
retrieving revision 1.444
diff -c -3 -p -r1.444 readelf.c
*** binutils/readelf.c	30 Apr 2009 15:47:13 -0000	1.444
--- binutils/readelf.c	28 May 2009 10:49:36 -0000
*************** display_debug_section (Elf_Internal_Shdr
*** 8539,8544 ****
--- 8539,8553 ----
        printf (_("\nSection '%s' has no debugging data.\n"), name);
        return 0;
      }
+   if (section->sh_type == SHT_NOBITS)
+     {
+       /* There is no point in dumping the contents of a debugging section
+ 	 which has the NOBITS type - the bits in the file will be random.
+ 	 This can happen when a file containing a .eh_frame section is
+ 	 stripped with the --only-keep-debug command line option.  */
+       printf (_("section '%s' has the NOBITS type - its contents are unreliable.\n"), name);
+       return 0;
+     }
  
    if (const_strneq (name, ".gnu.linkonce.wi."))
      name = ".debug_info";