Use bfd id to validate dwarf2 cache

Using a bfd pointer to validate the cache isn't very robust.  If a bfd
is closed somehow without clearing the cache, then it's possible that
another bfd is opened using the same memory and thus orig_bfd compares
equal to the new bfd.

	* dwarf2.c (struct dwarf2_debug): Add orig_bfd_id.  Delete
	orig_bfd.
	(_bfd_dwarf2_slurp_debug_info): Validate stash with orig_bfd_id.

diff --git a/bfd/dwarf2.c b/bfd/dwarf2.c
index 151ed0237ca025d114a37b7e2e2decd6ac73c193..e93a331c5b4bd2ecadd640c0cffcac29dae3974a 100644 (file)
--- a/bfd/dwarf2.c
+++ b/bfd/dwarf2.c
@@ -292,12 +292,6 @@ struct dwarf2_debug
   /* Per-file stuff.  */
   struct dwarf2_debug_file f, alt;
 
-  /* Pointer to the original bfd for which debug was loaded.  This is what
-     we use to compare and so check that the cached debug data is still
-     valid - it saves having to possibly dereference the gnu_debuglink each
-     time.  */
-  bfd *orig_bfd;
-
   /* If the most recent call to bfd_find_nearest_line was given an
      address in an inlined function, preserve a pointer into the
      calling chain for subsequent calls to bfd_find_inliner_info to
@@ -315,6 +309,9 @@ struct dwarf2_debug
   /* Array of sections with adjusted VMA.  */
   struct adjusted_section *adjusted_sections;
 
+  /* Used to validate the cached debug data.  */
+  unsigned int orig_bfd_id;
+
   /* Number of times find_line is called.  This is used in
      the heuristic for enabling the info hash tables.  */
   int info_hash_count;
@@ -5401,7 +5398,7 @@ _bfd_dwarf2_slurp_debug_info (bfd *abfd, bfd *debug_bfd,
 
   if (stash != NULL)
     {
-      if (stash->orig_bfd == abfd
+      if (stash->orig_bfd_id == abfd->id
          && section_vma_same (abfd, stash))
        {
          /* Check that we did previously find some debug information
@@ -5425,7 +5422,7 @@ _bfd_dwarf2_slurp_debug_info (bfd *abfd, bfd *debug_bfd,
        return false;
       *pinfo = stash;
     }
-  stash->orig_bfd = abfd;
+  stash->orig_bfd_id = abfd->id;
   stash->debug_sections = debug_sections;
   stash->f.syms = symbols;
   if (!save_section_vma (abfd, stash))