daily update

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

diff --git a/bfd/linker.c b/bfd/linker.c
index 76bc70af0933c2351fe014172722e7f2572825aa..2b52ba965105930a4db2aa149a88d0181e0511f6 100644 (file)
--- a/bfd/linker.c
+++ b/bfd/linker.c
@@ -223,7 +223,10 @@ SUBSUBSECTION
        archive and decide which elements of the archive should be
        included in the link.  For each such element it must call the
        <<add_archive_element>> linker callback, and it must add the
-       symbols from the object file to the linker hash table.
+       symbols from the object file to the linker hash table.  (The
+       callback may in fact indicate that a replacement BFD should be
+       used, in which case the symbols from that BFD should be added
+       to the linker hash table instead.)
 
 @findex _bfd_generic_link_add_archive_symbols
        In most cases the work of looking through the symbols in the
@@ -243,9 +246,13 @@ SUBSUBSECTION
        element should be included in the link.  If the element is to
        be included, the <<add_archive_element>> linker callback
        routine must be called with the element as an argument, and
-       the elements symbols must be added to the linker hash table
+       the element's symbols must be added to the linker hash table
        just as though the element had itself been passed to the
-       <<_bfd_link_add_symbols>> function.
+       <<_bfd_link_add_symbols>> function.  The <<add_archive_element>>
+       callback has the option to indicate that it would like to
+       replace the element archive with a substitute BFD, in which
+       case it is the symbols of that substitute BFD that must be
+       added to the linker hash table instead.
 
        When the a.out <<_bfd_link_add_symbols>> function receives an
        archive, it calls <<_bfd_generic_link_add_archive_symbols>>
@@ -257,7 +264,8 @@ SUBSUBSECTION
        symbol) it calls the <<add_archive_element>> callback and then
        <<aout_link_check_archive_element>> calls
        <<aout_link_add_symbols>> to actually add the symbols to the
-       linker hash table.
+       linker hash table - possibly those of a substitute BFD, if the
+       <<add_archive_element>> callback avails itself of that option.
 
        The ECOFF back end is unusual in that it does not normally
        call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF
@@ -957,8 +965,10 @@ archive_hash_table_init
    included.  CHECKFN should set *PNEEDED to TRUE if the object file
    should be included, and must also call the bfd_link_info
    add_archive_element callback function and handle adding the symbols
-   to the global hash table.  CHECKFN should only return FALSE if some
-   sort of error occurs.
+   to the global hash table.  CHECKFN must notice if the callback
+   indicates a substitute BFD, and arrange to add those symbols instead
+   if it does so.  CHECKFN should only return FALSE if some sort of
+   error occurs.
 
    For some formats, such as a.out, it is possible to look through an
    object file but not actually include it in the link.  The
@@ -1213,10 +1223,17 @@ generic_link_check_archive_element (bfd *abfd,
        {
          bfd_size_type symcount;
          asymbol **symbols;
+         bfd *oldbfd = abfd;
 
          /* This object file defines this symbol, so pull it in.  */
-         if (! (*info->callbacks->add_archive_element) (info, abfd,
-                                                        bfd_asymbol_name (p)))
+         if (!(*info->callbacks
+               ->add_archive_element) (info, abfd, bfd_asymbol_name (p),
+                                       &abfd))
+           return FALSE;
+         /* Potentially, the add_archive_element hook may have set a
+            substitute BFD for us.  */
+         if (abfd != oldbfd
+             && !bfd_generic_link_read_symbols (abfd))
            return FALSE;
          symcount = _bfd_generic_link_get_symcount (abfd);
          symbols = _bfd_generic_link_get_symbols (abfd);
@@ -1241,9 +1258,13 @@ generic_link_check_archive_element (bfd *abfd,
              /* This symbol was created as undefined from outside
                 BFD.  We assume that we should link in the object
                 file.  This is for the -u option in the linker.  */
-             if (! (*info->callbacks->add_archive_element)
-                 (info, abfd, bfd_asymbol_name (p)))
+             if (!(*info->callbacks
+                   ->add_archive_element) (info, abfd, bfd_asymbol_name (p),
+                                           &abfd))
                return FALSE;
+             /* Potentially, the add_archive_element hook may have set a
+                substitute BFD for us.  But no symbols are going to get
+                registered by anything we're returning to from here.  */
              *pneeded = TRUE;
              return TRUE;
            }