* bfd.c (struct bfd_preserve): New.

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

diff --git a/bfd/bfd.c b/bfd/bfd.c
index cff7119ee29555b479f1221d61dfeee5f4fe9363..5412ac8bfc9ce724f785d1661fb973d00a154c8f 100644 (file)
--- a/bfd/bfd.c
+++ b/bfd/bfd.c
@@ -1392,3 +1392,133 @@ bfd_alt_mach_code (abfd, alternative)
 
   return false;
 }
+
+/*
+CODE_FRAGMENT
+
+.struct bfd_preserve
+.{
+.  PTR marker;
+.  PTR tdata;
+.  flagword flags;
+.  const struct bfd_arch_info *arch_info;
+.  struct sec *sections;
+.  struct sec **section_tail;
+.  unsigned int section_count;
+.  struct bfd_hash_table section_htab;
+.};
+.
+*/
+
+/*
+FUNCTION
+       bfd_preserve_save
+
+SYNOPSIS
+       boolean bfd_preserve_save (bfd *, struct bfd_preserve *);
+
+DESCRIPTION
+       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 and
+       reinitializes the bfd.
+
+*/
+
+boolean
+bfd_preserve_save (abfd, preserve)
+     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_tail = abfd->section_tail;
+  preserve->section_count = abfd->section_count;
+  preserve->section_htab = abfd->section_htab;
+
+  if (! bfd_hash_table_init (&abfd->section_htab, bfd_section_hash_newfunc))
+    return false;
+
+  abfd->tdata.any = NULL;
+  abfd->arch_info = &bfd_default_arch_struct;
+  abfd->flags = 0;
+
+  abfd->sections = NULL;
+  abfd->section_tail = &abfd->sections;
+  abfd->section_count = 0;
+
+  return true;
+}
+
+/*
+FUNCTION
+       bfd_preserve_restore
+
+SYNOPSIS
+       void bfd_preserve_restore (bfd *, struct bfd_preserve *);
+
+DESCRIPTION
+       This function restores bfd state saved by bfd_preserve_save.
+       If MARKER is non-NULL in struct bfd_preserve then that block
+       and all subsequently bfd_alloc'd memory is freed.
+
+*/
+
+void
+bfd_preserve_restore (abfd, preserve)
+     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_tail = preserve->section_tail;
+  abfd->section_count = preserve->section_count;
+
+  /* bfd_release frees all memory more recently bfd_alloc'd than
+     its arg, as well as its arg.  */
+  if (preserve->marker != NULL)
+    {
+      bfd_release (abfd, preserve->marker);
+      preserve->marker = NULL;
+    }
+}
+
+/*
+FUNCTION
+       bfd_preserve_finish
+
+SYNOPSIS
+       void bfd_preserve_finish (bfd *, struct bfd_preserve *);
+
+DESCRIPTION
+       This function should be called when the bfd state saved by
+       bfd_preserve_save is no longer needed.  ie. when the back-end
+       object_p function returns with success.
+
+*/
+
+void
+bfd_preserve_finish (abfd, preserve)
+     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);
+}