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Hide dynamic symbols in discarded sections
- From: Alan Modra <amodra at gmail dot com>
- To: binutils at sourceware dot org
- Date: Tue, 3 Jul 2018 16:49:26 +0930
- Subject: Hide dynamic symbols in discarded sections
This is a followup to git commit 97196564c7 "Strip global symbol
defined in discarded section". If a symbol defined in a discarded
section was dynamic, that patch left .dynsym with holes (ie. all zero
entries). For example, the following from libstdc++.so:
Symbol table '.dynsym' contains 6090 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000000a74e0 0 SECTION LOCAL DEFAULT 10
2: 0000000000264180 0 SECTION LOCAL DEFAULT 17
3: 0000000000000000 0 NOTYPE WEAK DEFAULT UND _ITM_addUserCommitAction
4: 0000000000000000 0 NOTYPE WEAK DEFAULT UND _ITM_memcpyRtWn
5: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
readelf: Warning: local symbol 5 found at index >= .dynsym's sh_info value of 3
6: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
readelf: Warning: local symbol 6 found at index >= .dynsym's sh_info value of 3
[snip]
This patch removes the symbols from .dynsym too.
PR 17550
* elflink.c (_bfd_elf_fix_symbol_flags): Hide dynamic symbols
in discarded sections.
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 36e0c37c8e..e5592b023a 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -2853,10 +2853,14 @@ _bfd_elf_fix_symbol_flags (struct elf_link_hash_entry *h,
&& (h->root.u.def.section->owner->flags & (DYNAMIC | BFD_PLUGIN)) == 0)
h->def_regular = 1;
+ /* Symbols defined in discarded sections shouldn't be dynamic. */
+ if (h->root.type == bfd_link_hash_undefined && h->indx == -3)
+ (*bed->elf_backend_hide_symbol) (eif->info, h, TRUE);
+
/* If a weak undefined symbol has non-default visibility, we also
hide it from the dynamic linker. */
- if (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
- && h->root.type == bfd_link_hash_undefweak)
+ else if (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
+ && h->root.type == bfd_link_hash_undefweak)
(*bed->elf_backend_hide_symbol) (eif->info, h, TRUE);
/* A hidden versioned symbol in executable should be forced local if
--
Alan Modra
Australia Development Lab, IBM