XCOFF linker segmentation fault

[Alan Modra <amodra at gmail dot com>]

The XCOFF linker temporarily trims the output bfd section list,
without adjusting section_count to suit.  This is a little rude, but
the dwarf line number code can easily cope with this situation.  So
check for a NULL end of list as well as limiting the saved section
VMAs to the first section_count list entries.

Also fixes
-FAIL: Weak test 3 (main, static) (32-bit)
-FAIL: Weak test 3 (main, static) (64-bit)

	PR 24596
	* dwarf2.c (save_section_vma, section_vma_same): Check for NULL
	end of section list as well as section_count.
	* xcofflink.c (xcoff_link_add_symbols): Fix temporarily changed
	section list before returning error.

diff --git a/bfd/dwarf2.c b/bfd/dwarf2.c
index 76af009e33..65c4161171 100644
--- a/bfd/dwarf2.c
+++ b/bfd/dwarf2.c
@@ -4272,7 +4272,9 @@ save_section_vma (const bfd *abfd, struct dwarf2_debug *stash)
   if (stash->sec_vma == NULL)
     return FALSE;
   stash->sec_vma_count = abfd->section_count;
-  for (i = 0, s = abfd->sections; i < abfd->section_count; i++, s = s->next)
+  for (i = 0, s = abfd->sections;
+       s != NULL && i < abfd->section_count;
+       i++, s = s->next)
     {
       if (s->output_section != NULL)
 	stash->sec_vma[i] = s->output_section->vma + s->output_offset;
@@ -4301,7 +4303,9 @@ section_vma_same (const bfd *abfd, const struct dwarf2_debug *stash)
   if (abfd->section_count != stash->sec_vma_count)
     return FALSE;
 
-  for (i = 0, s = abfd->sections; i < abfd->section_count; i++, s = s->next)
+  for (i = 0, s = abfd->sections;
+       s != NULL && i < abfd->section_count;
+       i++, s = s->next)
     {
       bfd_vma vma;
 
diff --git a/bfd/xcofflink.c b/bfd/xcofflink.c
index e7f50d1690..f9c12e40f3 100644
--- a/bfd/xcofflink.c
+++ b/bfd/xcofflink.c
@@ -1882,7 +1882,7 @@ xcoff_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
 
       if (EXTERN_SYM_P (sym.n_sclass))
 	{
-	  bfd_boolean copy;
+	  bfd_boolean copy, ok;
 	  flagword flags;
 
 	  BFD_ASSERT (section != NULL);
@@ -2022,12 +2022,12 @@ xcoff_link_add_symbols (bfd *abfd, struct bfd_link_info *info)
 	  BFD_ASSERT (last_real->next == first_csect);
 	  last_real->next = NULL;
 	  flags = (sym.n_sclass == C_EXT ? BSF_GLOBAL : BSF_WEAK);
-	  if (! (_bfd_generic_link_add_one_symbol
-		 (info, abfd, name, flags, section, value,
-		  NULL, copy, TRUE,
-		  (struct bfd_link_hash_entry **) sym_hash)))
-	    goto error_return;
+	  ok = (_bfd_generic_link_add_one_symbol
+		(info, abfd, name, flags, section, value, NULL, copy, TRUE,
+		 (struct bfd_link_hash_entry **) sym_hash));
 	  last_real->next = first_csect;
+	  if (!ok)
+	    goto error_return;
 
 	  if (smtyp == XTY_CM)
 	    {

-- 
Alan Modra
Australia Development Lab, IBM