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ARM: Raise incompatibility errors for shared objects

Daniel Jacobowitz drow@mvista.com
Mon Oct 27 15:35:00 GMT 2003 
I was recently told that the ARM linker didn't complain when it used a
shared object marked as VFP and a binary marked FPA, or vice versa.  The
problem turned out to be some code in elf32_arm_merge_private_bfd_data
designed to skip archives with no contents; if I remember right this was
added for the linux kernel because the empty archives seemed to have the
wrong flags (since they were uninitialized).

Unfortunately, shared objects are linked by removing their sections, to
prevent them from being copied into the output file.  If one is used for
building new sections (e.g. .dynamic) then the warning triggers; if it
isn't, then the warning does not trigger.  This patch prevents skipping
DYNAMIC objects.

Patch is against 2.14 but also applies to HEAD.  OK?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

2003-10-24  Daniel Jacobowitz  <drow@mvista.com>

	* elf32-arm.h (elf32_arm_merge_private_bfd_data): Never skip dynamic
	objects.

--- binutils-2.14/bfd/elf32-arm.h.orig	2003-10-24 17:50:16.000000000 -0400
+++ binutils-2.14/bfd/elf32-arm.h	2003-10-24 17:53:25.000000000 -0400
@@ -2491,21 +2491,27 @@ elf32_arm_merge_private_bfd_data (ibfd, 
   if (in_flags == out_flags)
     return TRUE;
 
-  /* Check to see if the input BFD actually contains any sections.
-     If not, its flags may not have been initialised either, but it cannot
-     actually cause any incompatibility.  */
-  for (sec = ibfd->sections; sec != NULL; sec = sec->next)
-    {
-      /* Ignore synthetic glue sections.  */
-      if (strcmp (sec->name, ".glue_7")
-	  && strcmp (sec->name, ".glue_7t"))
-	{
-	  null_input_bfd = FALSE;
-	  break;
+  /* Check to see if the input BFD actually contains any sections.  If
+     not, its flags may not have been initialised either, but it
+     cannot actually cause any incompatibility.  Do not short-circuit
+     dynamic objects; their section list may be emptied by
+     elf_link_add_object_symbols.  */
+
+  if (!(ibfd->flags & DYNAMIC))
+    {
+      for (sec = ibfd->sections; sec != NULL; sec = sec->next)
+	{
+	  /* Ignore synthetic glue sections.  */
+	  if (strcmp (sec->name, ".glue_7")
+	      && strcmp (sec->name, ".glue_7t"))
+	    {
+	      null_input_bfd = FALSE;
+	      break;
+	    }
 	}
+      if (null_input_bfd)
+	return TRUE;
     }
-  if (null_input_bfd)
-    return TRUE;
 
   /* Complain about various flag mismatches.  */
   if (EF_ARM_EABI_VERSION (in_flags) != EF_ARM_EABI_VERSION (out_flags))
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