Fix i386-on-x86_64 debugging giving the warning:

	warning: Lowest section in system-supplied DSO at 0xffffe000 is .hash at ffffe0b4

[ Backport for RH GDB-6.6. ]

--- gdb-6.6/gdb/symfile.c	2007-10-08 19:52:06.000000000 +0200

+++ gdb-6.6/gdb/symfile.c	2007-10-08 19:49:27.000000000 +0200

@@ -597,6 +597,37 @@ default_symfile_offsets (struct objfile 

   init_objfile_sect_indices (objfile);

 }

+/* Find lowest loadable section to be used as starting point for continguous

+   sections. FIXME!! won't work without call to find .text first, but this

+   assumes text is lowest section.  vDSO was seen for i386-on-amd64 processes

+   to have no `.text' as it has `.text.vsyscall', `.text.sigreturn' etc.

+   instead.  Execution of this function has been delayed till it is really

+   needed as it is broken for vDSOs, fortunately it is never needed on

+   GNU/Linux.  */

+

+static CORE_ADDR

+find_lower_offset (struct objfile *objfile)

+{

+  asection *lower_sect;

+

+  lower_sect = bfd_get_section_by_name (objfile->obfd, ".text");

+  if (lower_sect == NULL)

+    bfd_map_over_sections (objfile->obfd, find_lowest_section,

+			   &lower_sect);

+  if (lower_sect == NULL)

+    warning (_("no loadable sections found in added symbol-file %s"),

+	     objfile->name);

+  else

+    if ((bfd_get_section_flags (objfile->obfd, lower_sect) & SEC_CODE) == 0)

+      warning (_("Lowest section in %s is %s at %s"),

+	       objfile->name,

+	       bfd_section_name (objfile->obfd, lower_sect),

+	       paddr (bfd_section_vma (objfile->obfd, lower_sect)));

+  if (lower_sect != NULL)

+    return bfd_section_vma (objfile->obfd, lower_sect);

+  else

+    return 0;

+}

 /* Process a symbol file, as either the main file or as a dynamically

    loaded file.

@@ -696,32 +727,11 @@ syms_from_objfile (struct objfile *objfi

      happens for the PA64 port.  */

   if (/*!mainline &&*/ addrs && addrs->other[0].name)

     {

-      asection *lower_sect;

       asection *sect;

-      CORE_ADDR lower_offset;

+      CORE_ADDR lower_offset = 0;	/* Shut up the GCC warning.  */

+      int lower_offset_set = 0;

       int i;

-      /* Find lowest loadable section to be used as starting point for

-         continguous sections. FIXME!! won't work without call to find

-	 .text first, but this assumes text is lowest section. */

-      lower_sect = bfd_get_section_by_name (objfile->obfd, ".text");

-      if (lower_sect == NULL)

-	bfd_map_over_sections (objfile->obfd, find_lowest_section,

-			       &lower_sect);

-      if (lower_sect == NULL)

-	warning (_("no loadable sections found in added symbol-file %s"),

-		 objfile->name);

-      else

-	if ((bfd_get_section_flags (objfile->obfd, lower_sect) & SEC_CODE) == 0)

-	  warning (_("Lowest section in %s is %s at %s"),

-		   objfile->name,

-		   bfd_section_name (objfile->obfd, lower_sect),

-		   paddr (bfd_section_vma (objfile->obfd, lower_sect)));

-      if (lower_sect != NULL)

- 	lower_offset = bfd_section_vma (objfile->obfd, lower_sect);

-      else

- 	lower_offset = 0;

-

       /* Calculate offsets for the loadable sections.

  	 FIXME! Sections must be in order of increasing loadable section

  	 so that contiguous sections can use the lower-offset!!!

@@ -743,6 +753,7 @@ syms_from_objfile (struct objfile *objfi

                     addrs->other[i].addr

                       -= bfd_section_vma (objfile->obfd, sect);

                     lower_offset = addrs->other[i].addr;

+		    lower_offset_set = 1;

                     /* This is the index used by BFD. */

                     addrs->other[i].sectindex = sect->index ;

                   }

@@ -755,7 +766,17 @@ syms_from_objfile (struct objfile *objfi

                   }

               }

             else

-              addrs->other[i].addr = lower_offset;

+	      {

+		/* Delay finding LOWER_OFFSET only if it is needed.  Otherwise

+		   we would print a warning to detect a values never used.  */

+		if (!lower_offset_set)

+		  {

+		    lower_offset = find_lower_offset (objfile);

+		    lower_offset_set = 1;

+		  }

+

+		addrs->other[i].addr = lower_offset;

+	      }

           }

     }