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--as-needed change wrt undefined weak symbols
- From: Alan Modra <amodra at gmail dot com>
- To: binutils at sourceware dot org
- Cc: Pierre Ossman <ossman at cendio dot se>
- Date: Mon, 14 Jan 2013 14:28:05 +1030
- Subject: --as-needed change wrt undefined weak symbols
Does anyone have objections or serious reservations on changing
--as-needed to require a strong reference? I'm in favour of excluding
weak references as that more closely follows the rules for ld
extracting objects from archives.
Now that http://sourceware.org/ml/binutils/2013-01/msg00165.html and
http://sourceware.org/ml/binutils/2013-01/msg00186.html have gone in I
think the following is all we need.
bfd/
PR ld/12549
elflink.c (elf_link_add_object_symbols): Exclude weak refs when
considering whether an --as-needed library is needed.
ld/
* ld.texinfo (--as-needed): Update.
ld/testsuite/
* ld-elf/pr14862.out: Expect no output.
Index: bfd/elflink.c
===================================================================
RCS file: /cvs/src/src/bfd/elflink.c,v
retrieving revision 1.463
diff -u -p -r1.463 elflink.c
--- bfd/elflink.c 13 Jan 2013 12:32:10 -0000 1.463
+++ bfd/elflink.c 14 Jan 2013 03:37:56 -0000
@@ -4480,8 +4480,8 @@ error_free_dyn:
if (!add_needed
&& definition
&& ((dynsym
- && h->ref_regular)
- || (h->ref_dynamic
+ && h->ref_regular_nonweak)
+ || (h->ref_dynamic_nonweak
&& (elf_dyn_lib_class (abfd) & DYN_AS_NEEDED) != 0
&& !on_needed_list (elf_dt_name (abfd), htab->needed))))
{
Index: ld/ld.texinfo
===================================================================
RCS file: /cvs/src/src/ld/ld.texinfo,v
retrieving revision 1.290
diff -u -p -r1.290 ld.texinfo
--- ld/ld.texinfo 7 Jan 2013 12:11:11 -0000 1.290
+++ ld/ld.texinfo 14 Jan 2013 03:37:57 -0000
@@ -1150,11 +1150,14 @@ on the command line after the @option{--
the linker will add a DT_NEEDED tag for each dynamic library mentioned
on the command line, regardless of whether the library is actually
needed or not. @option{--as-needed} causes a DT_NEEDED tag to only be
-emitted for a library that satisfies an undefined symbol reference
-from a regular object file or, if the library is not found in the
-DT_NEEDED lists of other libraries linked up to that point, an
-undefined symbol reference from another dynamic library.
-@option{--no-as-needed} restores the default behaviour.
+emitted for a library that @emph{at that point in the link} satisfies a
+non-weak undefined symbol reference from a regular object file or, if
+the library is not found in the DT_NEEDED lists of other libraries, a
+non-weak undefined symbol reference from another dynamic library.
+Object files or libraries appearing on the command line @emph{after}
+the library in question do not affect whether the library is seen as
+needed. This is similar to the rules for extraction of object files
+from archives. @option{--no-as-needed} restores the default behaviour.
@kindex --add-needed
@kindex --no-add-needed
Index: ld/testsuite/ld-elf/pr14862.out
===================================================================
RCS file: /cvs/src/src/ld/testsuite/ld-elf/pr14862.out,v
retrieving revision 1.1
diff -u -p -r1.1 pr14862.out
--- ld/testsuite/ld-elf/pr14862.out 20 Nov 2012 22:17:27 -0000 1.1
+++ ld/testsuite/ld-elf/pr14862.out 14 Jan 2013 03:37:57 -0000
@@ -1 +0,0 @@
-OK
--
Alan Modra
Australia Development Lab, IBM