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[deliverable/binutils-gdb.git] / bfd / format.c

diff --git a/bfd/format.c b/bfd/format.c
index cea9a23810a927e5d4734b7559e13875a8d03e0d..f34b1d484276a549add5b9a03d863cf054a85d07 100644 (file)
--- a/bfd/format.c
+++ b/bfd/format.c
@@ -1,6 +1,5 @@
 /* Generic BFD support for file formats.
 /* Generic BFD support for file formats.

-   Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1999, 2000, 2001, 2002,
-   2003, 2005, 2007 Free Software Foundation, Inc.
+   Copyright (C) 1990-2016 Free Software Foundation, Inc.

    Written by Cygnus Support.
 
    This file is part of BFD, the Binary File Descriptor library.
    Written by Cygnus Support.
 
    This file is part of BFD, the Binary File Descriptor library.


@@ -95,6 +94,91 @@ bfd_check_format (bfd *abfd, bfd_format format)
   return bfd_check_format_matches (abfd, format, NULL);
 }
 
   return bfd_check_format_matches (abfd, format, NULL);
 }
 

+struct bfd_preserve
+{
+  void *marker;
+  void *tdata;
+  flagword flags;
+  const struct bfd_arch_info *arch_info;
+  struct bfd_section *sections;
+  struct bfd_section *section_last;
+  unsigned int section_count;
+  struct bfd_hash_table section_htab;
+};
+
+/* When testing an object for compatibility with a particular target
+   back-end, the back-end object_p function needs to set up certain
+   fields in the bfd on successfully recognizing the object.  This
+   typically happens in a piecemeal fashion, with failures possible at
+   many points.  On failure, the bfd is supposed to be restored to its
+   initial state, which is virtually impossible.  However, restoring a
+   subset of the bfd state works in practice.  This function stores
+   the subset.  */
+
+static bfd_boolean
+bfd_preserve_save (bfd *abfd, struct bfd_preserve *preserve)
+{
+  preserve->tdata = abfd->tdata.any;
+  preserve->arch_info = abfd->arch_info;
+  preserve->flags = abfd->flags;
+  preserve->sections = abfd->sections;
+  preserve->section_last = abfd->section_last;
+  preserve->section_count = abfd->section_count;
+  preserve->section_htab = abfd->section_htab;
+  preserve->marker = bfd_alloc (abfd, 1);
+  if (preserve->marker == NULL)
+    return FALSE;
+
+  return bfd_hash_table_init (&abfd->section_htab, bfd_section_hash_newfunc,
+                             sizeof (struct section_hash_entry));
+}
+
+/* Clear out a subset of BFD state.  */
+
+static void
+bfd_reinit (bfd *abfd)
+{
+  abfd->tdata.any = NULL;
+  abfd->arch_info = &bfd_default_arch_struct;
+  abfd->flags &= BFD_FLAGS_SAVED;
+  bfd_section_list_clear (abfd);
+}
+
+/* Restores bfd state saved by bfd_preserve_save.  */
+
+static void
+bfd_preserve_restore (bfd *abfd, struct bfd_preserve *preserve)
+{
+  bfd_hash_table_free (&abfd->section_htab);
+
+  abfd->tdata.any = preserve->tdata;
+  abfd->arch_info = preserve->arch_info;
+  abfd->flags = preserve->flags;
+  abfd->section_htab = preserve->section_htab;
+  abfd->sections = preserve->sections;
+  abfd->section_last = preserve->section_last;
+  abfd->section_count = preserve->section_count;
+
+  /* bfd_release frees all memory more recently bfd_alloc'd than
+     its arg, as well as its arg.  */
+  bfd_release (abfd, preserve->marker);
+  preserve->marker = NULL;
+}
+
+/* Called when the bfd state saved by bfd_preserve_save is no longer
+   needed.  */
+
+static void
+bfd_preserve_finish (bfd *abfd ATTRIBUTE_UNUSED, struct bfd_preserve *preserve)
+{
+  /* It would be nice to be able to free more memory here, eg. old
+     tdata, but that's not possible since these blocks are sitting
+     inside bfd_alloc'd memory.  The section hash is on a separate
+     objalloc.  */
+  bfd_hash_table_free (&preserve->section_htab);
+  preserve->marker = NULL;
+}
+

 /*
 FUNCTION
        bfd_check_format_matches
 /*
 FUNCTION
        bfd_check_format_matches


@@ -119,11 +203,15 @@ bfd_boolean
 bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
 {
   extern const bfd_target binary_vec;
 bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
 {
   extern const bfd_target binary_vec;

+#if BFD_SUPPORTS_PLUGINS
+  extern const bfd_target plugin_vec;
+#endif

   const bfd_target * const *target;
   const bfd_target **matching_vector = NULL;
   const bfd_target * const *target;
   const bfd_target **matching_vector = NULL;

-  const bfd_target *save_targ, *right_targ, *ar_right_targ;
-  int match_count;
+  const bfd_target *save_targ, *right_targ, *ar_right_targ, *match_targ;
+  int match_count, best_count, best_match;

   int ar_match_index;
   int ar_match_index;

+  struct bfd_preserve preserve;

 
   if (matching != NULL)
     *matching = NULL;
 
   if (matching != NULL)
     *matching = NULL;


@@ -138,27 +226,20 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
   if (abfd->format != bfd_unknown)
     return abfd->format == format;
 
   if (abfd->format != bfd_unknown)
     return abfd->format == format;
 

-  /* Since the target type was defaulted, check them
-     all in the hope that one will be uniquely recognized.  */
-  save_targ = abfd->xvec;
-  match_count = 0;
-  ar_match_index = _bfd_target_vector_entries;
-

   if (matching != NULL || *bfd_associated_vector != NULL)
     {
       bfd_size_type amt;
 
       amt = sizeof (*matching_vector) * 2 * _bfd_target_vector_entries;
   if (matching != NULL || *bfd_associated_vector != NULL)
     {
       bfd_size_type amt;
 
       amt = sizeof (*matching_vector) * 2 * _bfd_target_vector_entries;

-      matching_vector = bfd_malloc (amt);
+      matching_vector = (const bfd_target **) bfd_malloc (amt);

       if (!matching_vector)
        return FALSE;
     }
 
       if (!matching_vector)
        return FALSE;
     }
 

-  right_targ = 0;
-  ar_right_targ = 0;
-

   /* Presume the answer is yes.  */
   abfd->format = format;
   /* Presume the answer is yes.  */
   abfd->format = format;

+  save_targ = abfd->xvec;
+  preserve.marker = NULL;

 
   /* If the target type was explicitly specified, just check that target.  */
   if (!abfd->target_defaulted)
 
   /* If the target type was explicitly specified, just check that target.  */
   if (!abfd->target_defaulted)


@@ -187,17 +268,33 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
        goto err_unrecog;
     }
 
        goto err_unrecog;
     }
 

+  /* Since the target type was defaulted, check them all in the hope
+     that one will be uniquely recognized.  */
+  right_targ = NULL;
+  ar_right_targ = NULL;
+  match_targ = NULL;
+  best_match = 256;
+  best_count = 0;
+  match_count = 0;
+  ar_match_index = _bfd_target_vector_entries;
+

   for (target = bfd_target_vector; *target != NULL; target++)
     {
       const bfd_target *temp;
   for (target = bfd_target_vector; *target != NULL; target++)
     {
       const bfd_target *temp;

-      bfd_error_type err;

 
       /* Don't check the default target twice.  */
       if (*target == &binary_vec
 
       /* Don't check the default target twice.  */
       if (*target == &binary_vec

-         || (!abfd->target_defaulted && *target == save_targ))
+         || (!abfd->target_defaulted && *target == save_targ)
+         || (*target)->match_priority > best_match)

        continue;
 
        continue;
 

-      abfd->xvec = *target;    /* Change BFD's target temporarily.  */
+      /* If we already tried a match, the bfd is modified and may
+        have sections attached, which will confuse the next
+        _bfd_check_format call.  */
+      bfd_reinit (abfd);
+
+      /* Change BFD's target temporarily.  */
+      abfd->xvec = *target;

 
       if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
        goto err_ret;
 
       if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
        goto err_ret;


@@ -209,41 +306,68 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
       bfd_set_error (bfd_error_wrong_format);
 
       temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
       bfd_set_error (bfd_error_wrong_format);
 
       temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));

-

       if (temp)
        {
       if (temp)
        {

-         /* This format checks out as ok!  */
-         right_targ = temp;
-
-         /* If this is the default target, accept it, even if other
-            targets might match.  People who want those other targets
-            have to set the GNUTARGET variable.  */
-         if (temp == bfd_default_vector[0])
+         int match_priority = temp->match_priority;
+#if BFD_SUPPORTS_PLUGINS
+         /* If this object can be handled by a plugin, give that the
+            lowest priority; objects both handled by a plugin and
+            with an underlying object format will be claimed
+            separately by the plugin.  */
+         if (*target == &plugin_vec)
+           match_priority = (*target)->match_priority;
+#endif
+
+         match_targ = temp;
+         if (preserve.marker != NULL)
+           bfd_preserve_finish (abfd, &preserve);
+
+         if (abfd->format != bfd_archive
+             || (bfd_has_map (abfd)
+                 && bfd_get_error () != bfd_error_wrong_object_format))

            {
            {

-             match_count = 1;
-             break;
+             /* This format checks out as ok!  */
+             right_targ = temp;
+
+             /* If this is the default target, accept it, even if
+                other targets might match.  People who want those
+                other targets have to set the GNUTARGET variable.  */
+             if (temp == bfd_default_vector[0])
+               goto ok_ret;
+
+             if (matching_vector)
+               matching_vector[match_count] = temp;
+             match_count++;
+
+             if (match_priority < best_match)
+               {
+                 best_match = match_priority;
+                 best_count = 0;
+               }
+             best_count++;
+           }
+         else
+           {
+             /* An archive with no armap or objects of the wrong
+                type.  We want this target to match if we get no
+                better matches.  */
+             if (ar_right_targ != bfd_default_vector[0])
+               ar_right_targ = *target;
+             if (matching_vector)
+               matching_vector[ar_match_index] = *target;
+             ar_match_index++;

            }
 
            }
 

-         if (matching_vector)
-           matching_vector[match_count] = temp;
-         match_count++;
-       }
-      else if ((err = bfd_get_error ()) == bfd_error_wrong_object_format
-              || err == bfd_error_file_ambiguously_recognized)
-       {
-         /* An archive with objects of the wrong type, or an
-            ambiguous match.  We want this target to match if we get
-            no better matches.  */
-         if (ar_right_targ != bfd_default_vector[0])
-           ar_right_targ = *target;
-         if (matching_vector)
-           matching_vector[ar_match_index] = *target;
-         ar_match_index++;
+         if (!bfd_preserve_save (abfd, &preserve))
+           goto err_ret;

        }
        }

-      else if (err != bfd_error_wrong_format)
+      else if (bfd_get_error () != bfd_error_wrong_format)

        goto err_ret;
     }
 
        goto err_ret;
     }
 

+  if (best_count == 1)
+    match_count = 1;
+

   if (match_count == 0)
     {
       /* Try partial matches.  */
   if (match_count == 0)
     {
       /* Try partial matches.  */


@@ -264,6 +388,9 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
        }
     }
 
        }
     }
 

+  /* We have more than one equally good match.  If any of the best
+     matches is a target in config.bfd targ_defvec or targ_selvecs,
+     choose it.  */

   if (match_count > 1)
     {
       const bfd_target * const *assoc = bfd_associated_vector;
   if (match_count > 1)
     {
       const bfd_target * const *assoc = bfd_associated_vector;


@@ -273,7 +400,8 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
          int i = match_count;
 
          while (--i >= 0)
          int i = match_count;
 
          while (--i >= 0)

-           if (matching_vector[i] == right_targ)
+           if (matching_vector[i] == right_targ
+               && right_targ->match_priority <= best_match)

              break;
 
          if (i >= 0)
              break;
 
          if (i >= 0)


@@ -284,11 +412,45 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
        }
     }
 
        }
     }
 

+  /* We still have more than one equally good match, and at least some
+     of the targets support match priority.  Choose the first of the
+     best matches.  */
+  if (matching_vector && match_count > 1 && best_count != match_count)
+    {
+      int i;
+
+      for (i = 0; i < match_count; i++)
+       {
+         right_targ = matching_vector[i];
+         if (right_targ->match_priority <= best_match)
+           break;
+       }
+      match_count = 1;
+    }
+
+  /* There is way too much undoing of half-known state here.  We
+     really shouldn't iterate on live bfd's.  Note that saving the
+     whole bfd and restoring it would be even worse; the first thing
+     you notice is that the cached bfd file position gets out of sync.  */
+  if (preserve.marker != NULL)
+    bfd_preserve_restore (abfd, &preserve);
+

   if (match_count == 1)
     {
   if (match_count == 1)
     {

-    ok_ret:
-      abfd->xvec = right_targ;         /* Change BFD's target permanently.  */
+      abfd->xvec = right_targ;
+      /* If we come out of the loop knowing that the last target that
+        matched is the one we want, then ABFD should still be in a usable
+        state (except possibly for XVEC).  */
+      if (match_targ != right_targ)
+       {
+         bfd_reinit (abfd);
+         if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0)
+           goto err_ret;
+         match_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
+         BFD_ASSERT (match_targ != NULL);
+       }

 
 

+    ok_ret:

       /* If the file was opened for update, then `output_has_begun'
         some time ago when the file was created.  Do not recompute
         sections sizes or alignments in _bfd_set_section_contents.
       /* If the file was opened for update, then `output_has_begun'
         some time ago when the file was created.  Do not recompute
         sections sizes or alignments in _bfd_set_section_contents.


@@ -299,7 +461,9 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
 
       if (matching_vector)
        free (matching_vector);
 
       if (matching_vector)
        free (matching_vector);

-      return TRUE;                     /* File position has moved, BTW.  */
+
+      /* File position has moved, BTW.  */
+      return TRUE;

     }
 
   if (match_count == 0)
     }
 
   if (match_count == 0)


@@ -311,11 +475,14 @@ bfd_check_format_matches (bfd *abfd, bfd_format format, char ***matching)
       abfd->format = bfd_unknown;
       if (matching_vector)
        free (matching_vector);
       abfd->format = bfd_unknown;
       if (matching_vector)
        free (matching_vector);

+      if (preserve.marker != NULL)
+       bfd_preserve_restore (abfd, &preserve);

       return FALSE;
     }
 
       return FALSE;
     }
 

-  abfd->xvec = save_targ;              /* Restore original target type.  */
-  abfd->format = bfd_unknown;          /* Restore original format.  */
+  /* Restore original target type and format.  */
+  abfd->xvec = save_targ;
+  abfd->format = bfd_unknown;

   bfd_set_error (bfd_error_file_ambiguously_recognized);
 
   if (matching)
   bfd_set_error (bfd_error_file_ambiguously_recognized);
 
   if (matching)