Fix GDB crash caused by discarding grouped debug sections

Keep a group containing just debug sections or the other special
sections we currently mark against garbage collection.

	* elflink.c (_bfd_elf_gc_mark_debug_special_section_group): New
	function.
	(_bfd_elf_gc_mark_extra_sections): Use it.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 234d559..a3e1d8f 100644 (file)
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2015-01-12  Terry Guo  <terry.guo@arm.com>
+
+       * elflink.c (_bfd_elf_gc_mark_debug_special_section_group): New
+       function.
+       (_bfd_elf_gc_mark_extra_sections): Use it.
+
 2015-01-11  H.J. Lu  <hongjiu.lu@intel.com>
 
        PR ld/17827

diff --git a/bfd/elflink.c b/bfd/elflink.c
index 66cf1ed..73d2360 100644 (file)
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -11971,6 +11971,47 @@ _bfd_elf_gc_mark (struct bfd_link_info *info,
   return ret;
 }
 
+/* Scan and mark sections in a special or debug section group.  */
+
+static void
+_bfd_elf_gc_mark_debug_special_section_group (asection *grp)
+{
+  /* Point to first section of section group.  */
+  asection *ssec;
+  /* Used to iterate the section group.  */
+  asection *msec;
+
+  bfd_boolean is_special_grp = TRUE;
+  bfd_boolean is_debug_grp = TRUE;
+
+  /* First scan to see if group contains any section other than debug
+     and special section.  */
+  ssec = msec = elf_next_in_group (grp);
+  do
+    {
+      if ((msec->flags & SEC_DEBUGGING) == 0)
+       is_debug_grp = FALSE;
+
+      if ((msec->flags & (SEC_ALLOC | SEC_LOAD | SEC_RELOC)) != 0)
+       is_special_grp = FALSE;
+
+      msec = elf_next_in_group (msec);
+    }
+  while (msec != ssec);
+
+  /* If this is a pure debug section group or pure special section group,
+     keep all sections in this group.  */
+  if (is_debug_grp || is_special_grp)
+    {
+      do
+       {
+         msec->gc_mark = 1;
+         msec = elf_next_in_group (msec);
+       }
+      while (msec != ssec);
+    }
+}
+
 /* Keep debug and special sections.  */
 
 bfd_boolean
@@ -12011,13 +12052,17 @@ _bfd_elf_gc_mark_extra_sections (struct bfd_link_info *info,
        continue;
 
       /* Keep debug and special sections like .comment when they are
-        not part of a group, or when we have single-member groups.  */
+        not part of a group.  Also keep section groups that contain
+        just debug sections or special sections.  */
       for (isec = ibfd->sections; isec != NULL; isec = isec->next)
-       if ((elf_next_in_group (isec) == NULL
-            || elf_next_in_group (isec) == isec)
-           && ((isec->flags & SEC_DEBUGGING) != 0
-               || (isec->flags & (SEC_ALLOC | SEC_LOAD | SEC_RELOC)) == 0))
-         isec->gc_mark = 1;
+       {
+         if ((isec->flags & SEC_GROUP) != 0)
+           _bfd_elf_gc_mark_debug_special_section_group (isec);
+         else if (((isec->flags & SEC_DEBUGGING) != 0
+                   || (isec->flags & (SEC_ALLOC | SEC_LOAD | SEC_RELOC)) == 0)
+                  && elf_next_in_group (isec) == NULL)
+           isec->gc_mark = 1;
+       }
 
       if (! debug_frag_seen)
        continue;