* elflink.c (_bfd_elf_gc_mark_extra_sections): Remove mark from

	fragmented .debug_line sections associated with unmarked code
	sections.

	* dwarf.c (read_debug_line_header): New function.  Reads in a
	header in a .debug_line section.
	(display_debug_lines_raw): Use new function.  Handle fragmentary
	.debug_line sections.
	(display_debug_lines_decoded): Likewise.
	* readelf.c (process_section_headers): Handle fragmenatry
	.debug_line sections.
	(display_debug_section): Likewise.

	* as.c (Options): Add -gdwarf-sections.
	(parse_args): Likewise.
	* as.h (flag_dwarf_sections): Declare.
	* dwarf2dbg.c (emit_fixed_inc_line_addr): Skip section changes.
	(process_entries): When -gdwarf-sections is enabled generate
	fragmentary .debug_line sections.
	(out_debug_line): Set the section for the .debug_line section end
	symbol.
	* doc/as.texinfo: Document -gdwarf-sections.
	* NEWS: Mention -gdwarf-sections.

	* gas/elf/dwarf2-3.d: Fix expected readelf output.

	* scripttempl/DWARF.sc: Add support for .debug_line.* and
	.debug_line_end.

1 files changed, 50 insertions, 4 deletions

diff --git a/bfd/elflink.c b/bfd/elflink.c
index 313d89e8e0..84ac1f2496 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -11814,23 +11814,30 @@ _bfd_elf_gc_mark_extra_sections (struct bfd_link_info *info,
     {
       asection *isec;
       bfd_boolean some_kept;
+      bfd_boolean debug_frag_seen;
 
       if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour)
 	continue;
 
-      /* Ensure all linker created sections are kept, and see whether
-	 any other section is already marked.  */
-      some_kept = FALSE;
+      /* Ensure all linker created sections are kept,
+	 see if any other section is already marked,
+	 and note if we have any fragmented debug sections.  */
+      debug_frag_seen = some_kept = FALSE;
       for (isec = ibfd->sections; isec != NULL; isec = isec->next)
 	{
 	  if ((isec->flags & SEC_LINKER_CREATED) != 0)
 	    isec->gc_mark = 1;
 	  else if (isec->gc_mark)
 	    some_kept = TRUE;
+
+	  if (debug_frag_seen == FALSE
+	      && (isec->flags & SEC_DEBUGGING)
+	      && CONST_STRNEQ (isec->name, ".debug_line."))
+	    debug_frag_seen = TRUE;
 	}
 
       /* If no section in this file will be kept, then we can
-	 toss out debug sections.  */
+	 toss out the debug and special sections.  */
       if (!some_kept)
 	continue;
 
@@ -11842,6 +11849,45 @@ _bfd_elf_gc_mark_extra_sections (struct bfd_link_info *info,
 	    && ((isec->flags & SEC_DEBUGGING) != 0
 		|| (isec->flags & (SEC_ALLOC | SEC_LOAD | SEC_RELOC)) == 0))
 	  isec->gc_mark = 1;
+
+      if (! debug_frag_seen)
+	continue;
+
+      /* Look for CODE sections which are going to be discarded,
+	 and find and discard any fragmented debug sections which
+	 are associated with that code section.  */
+      for (isec = ibfd->sections; isec != NULL; isec = isec->next)
+	if ((isec->flags & SEC_CODE) != 0
+	    && isec->gc_mark == 0)
+	  {
+	    unsigned int ilen;
+	    asection *dsec;
+
+	    ilen = strlen (isec->name);
+
+	    /* Association is determined by the name of the debug section
+	       containing the name of the code section as a suffix.  For
+	       example .debug_line.text.foo is a debug section associated
+	       with .text.foo.  */
+	    for (dsec = ibfd->sections; dsec != NULL; dsec = dsec->next)
+	      {
+		unsigned int dlen;
+
+		if (dsec->gc_mark == 0
+		    || (dsec->flags & SEC_DEBUGGING) == 0)
+		  continue;
+
+		dlen = strlen (dsec->name);
+
+		if (dlen > ilen
+		    && strncmp (dsec->name + (dlen - ilen),
+				isec->name, ilen) == 0)
+		  {
+		    dsec->gc_mark = 0;
+		    break;
+		  }
+	      }
+	  }
     }
   return TRUE;
 }