Set SEC_KEEP on section XXX for undefined __start_XXX/__stop_XXX

bfd/

2010-01-07  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/11133
	* elflink.c (_bfd_elf_gc_mark_hook): Check section XXX for
	undefined __start_XXX/__stop_XXX in all input files and set
	SEC_KEEP.

ld/testsuite/

2010-01-07  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/11133
	* ld-gc/gc.exp: Run start.

	* ld-gc/start.d: New.
	* ld-gc/start.s: Likewise.

6 files changed, 59 insertions, 0 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 01950b4fc0..0f2e0e4dc1 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,12 @@
 2010-01-07  H.J. Lu  <hongjiu.lu@intel.com>
 
+	PR ld/11133
+	* elflink.c (_bfd_elf_gc_mark_hook): Check section XXX for
+	undefined __start_XXX/__stop_XXX in all input files and set
+	SEC_KEEP.
+
+2010-01-07  H.J. Lu  <hongjiu.lu@intel.com>
+
 	PR ld/11143
 	* elflink.c (elf_gc_sweep): Keep SHT_NOTE section.
 
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 284bff14d7..f9f804de73 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -11331,6 +11331,8 @@ _bfd_elf_gc_mark_hook (asection *sec,
 		       struct elf_link_hash_entry *h,
 		       Elf_Internal_Sym *sym)
 {
+  const char *sec_name;
+
   if (h != NULL)
     {
       switch (h->root.type)
@@ -11342,6 +11344,33 @@ _bfd_elf_gc_mark_hook (asection *sec,
 	case bfd_link_hash_common:
 	  return h->root.u.c.p->section;
 
+	case bfd_link_hash_undefined:
+	case bfd_link_hash_undefweak:
+	  /* To work around a glibc bug, keep all XXX input sections
+	     when there is an as yet undefined reference to __start_XXX
+	     or __stop_XXX symbols.  The linker will later define such
+	     symbols for orphan input sections that have a name
+	     representable as a C identifier.  */
+	  if (strncmp (h->root.root.string, "__start_", 8) == 0)
+	    sec_name = h->root.root.string + 8;
+	  else if (strncmp (h->root.root.string, "__stop_", 7) == 0)
+	    sec_name = h->root.root.string + 7;
+	  else
+	    sec_name = NULL;
+
+	  if (sec_name && *sec_name != '\0')
+	    {
+	      bfd *i;
+	      
+	      for (i = info->input_bfds; i; i = i->link_next)
+		{
+		  sec = bfd_get_section_by_name (i, sec_name);
+		  if (sec)
+		    sec->flags |= SEC_KEEP;
+		}
+	    }
+	  break;
+
 	default:
 	  break;
 	}
diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index 3320c13dbb..220a6d9160 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,5 +1,13 @@
 2010-01-07  H.J. Lu  <hongjiu.lu@intel.com>
 
+	PR ld/11133
+	* ld-gc/gc.exp: Run start.
+
+	* ld-gc/start.d: New.
+	* ld-gc/start.s: Likewise.
+
+2010-01-07  H.J. Lu  <hongjiu.lu@intel.com>
+
 	PR ld/11143
 	* ld-gc/gc.exp: Run abi-note.
 
diff --git a/ld/testsuite/ld-gc/gc.exp b/ld/testsuite/ld-gc/gc.exp
index 36df2338eb..c271a3d254 100644
--- a/ld/testsuite/ld-gc/gc.exp
+++ b/ld/testsuite/ld-gc/gc.exp
@@ -91,3 +91,4 @@ test_gc "Check --gc-section/-r/-u" "gcrel" $ld "-r --gc-sections -u used_func"
 
 run_dump_test "noent"
 run_dump_test "abi-note"
+run_dump_test "start"
diff --git a/ld/testsuite/ld-gc/start.d b/ld/testsuite/ld-gc/start.d
new file mode 100644
index 0000000000..a6f748fd78
--- /dev/null
+++ b/ld/testsuite/ld-gc/start.d
@@ -0,0 +1,8 @@
+#name: --gc-sections with __start_
+#ld: --gc-sections -e _start
+#nm: -n
+#target: *-*-linux*
+
+#...
+[0-9a-f]+ A +__start__foo
+#...
diff --git a/ld/testsuite/ld-gc/start.s b/ld/testsuite/ld-gc/start.s
new file mode 100644
index 0000000000..d9f1b2d070
--- /dev/null
+++ b/ld/testsuite/ld-gc/start.s
@@ -0,0 +1,6 @@
+.globl _start
+_start:
+	.long __start__foo
+	.section	_foo,"aw",%progbits
+foo:
+	.long	1