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author | Alan Modra <amodra@gmail.com> | 2014-01-13 13:51:16 +1030 |
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committer | Alan Modra <amodra@gmail.com> | 2014-01-13 15:04:15 +1030 |
commit | c7e17e05b647f6233c2062d038e5421686217816 (patch) | |
tree | 5a76b6781f9f40342b24ddd40ffa5b1e781a7ff6 /README | |
parent | 1a4416c4c7f02a73652429f4e8e8e966f55e3e8b (diff) | |
download | gdb-c7e17e05b647f6233c2062d038e5421686217816.zip gdb-c7e17e05b647f6233c2062d038e5421686217816.tar.gz gdb-c7e17e05b647f6233c2062d038e5421686217816.tar.bz2 |
Error on shared lib call to @local ifunc
On powerpc32, making ifuncs have non-default visibility in shared
libraries or pies can result in runtime failures. The problem is that
if gcc is told that a given function has non-default visibility, then
calls to that function are assumed to be local (which is true) and
thus need not go via a plt call stub (which is false for ifunc). If
the caller has no other reason to set up the got pointer (r30), code
won't be emitted to do so. However, a pic plt call stub makes use of
r30 to load the plt entry. So a call to an ifunc, which always needs
a plt entry, will fail.
This patch makes ld emit an error for the problem case, and allows
calls to non-default visibility ifuncs to work in normal executables.
I also fix some cases where ifuncs fail when using the old bss-plt.
* elf32-ppc.c (ppc_elf_check_relocs): For @local call to ifunc,
error when shared and force a plt call otherwise.
(ppc_elf_size_dynamic_sections): Don't emit DT_PPC_GOT unless
plt_type == PLT_NEW.
(ppc_elf_relocate_section): Add missing test to resolve ifuncs to
the appropriate call stub.
Diffstat (limited to 'README')
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