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.
This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
BFD is an object file library. It permits applications to use the
same routines to process object files regardless of their format.
BFD is used by the GNU debugger, assembler, linker, and the binary
utilities.
The documentation on using BFD is scanty and may be occasionally
incorrect. Pointers to documentation problems, or an entirely
rewritten manual, would be appreciated.
There is some BFD internals documentation in doc/bfdint.texi which may
help programmers who want to modify BFD.
BFD is normally built as part of another package. See the build
instructions for that package, probably in a README file in the
appropriate directory.
BFD supports the following configure options:
--target=TARGET
The default target for which to build the library. TARGET is
a configuration target triplet, such as sparc-sun-solaris.
--enable-targets=TARGET,TARGET,TARGET...
Additional targets the library should support. To include
support for all known targets, use --enable-targets=all.
--enable-64-bit-bfd
Include support for 64 bit targets. This is automatically
turned on if you explicitly request a 64 bit target, but not
for --enable-targets=all. This requires a compiler with a 64
bit integer type, such as gcc.
--enable-shared
Build BFD as a shared library.
--with-mmap
Use mmap when accessing files. This is faster on some hosts,
but slower on others. It may not work on all hosts.
Report bugs with BFD to bug-binutils@gnu.org.
Patches are encouraged. When sending patches, always send the output
of diff -u or diff -c from the original file to the new file. Do not
send default diff output. Do not make the diff from the new file to
the original file. Remember that any patch must not break other
systems. Remember that BFD must support cross compilation from any
host to any target, so patches which use ``#ifdef HOST'' are not
acceptable. Please also read the ``Reporting Bugs'' section of the
gcc manual.
Bug reports without patches will be remembered, but they may never get
fixed until somebody volunteers to fix them.
Copyright (C) 2012 Free Software Foundation, Inc.
Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.