GCC 5 will generate a relocation for protected symbol:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65248
when compiling for a shared library. It is undefined to access protected
symbol in IFUNC selector function inside a shared library.
PR gold/18628
* testsuite/ifuncdep2.c (global): Change protected to hidden.
* testsuite/ifuncmod1.c (global): Likewise.
* testsuite/ifuncmod5.c (global): Likewise.
* i386.cc (class Output_data_plt_i386): Update declarations.
Define Global_ifunc and Local_ifunc types. Add global_ifuncs_ and
local_ifuncs_ fields.
(Target_i386::do_plt_section_for_global): New function.
(Target_i386::do_plt_section_for_local): New function.
(Output_data_plt_i386::Output_data_plt_i386): Add symtab
parameter; change all callers. Initialize global_ifuncs_ and
local_ifuncs_. If doing a static link define __rel_iplt_start and
__rel_iplt_end.
(Output_data_plt_i386::add_entry): Handle IFUNC symbols.
(Output_data_plt_i386::add_local_ifunc_entry): New function.
(Output_data_plt_i386::do_write): Fix GOT entries for IFUNC
symbols.
(Target_i386::make_plt_section): New function, broken out of
make_plt_entry. Set sh_info field of .rel.plt to point to .plt.
(Target_i386::make_plt_entry): Call make_plt_section.
(Target_i386::make_local_ifunc_plt_entry): New function.
(Target_i386::Scan::reloc_needs_iplt_for_ifunc): New function.
(Target_i386::Scan::local): Handle IFUNC symbols. Add
R_386_IRELATIVE to switch.
(Target_i386::Scan::global): Likewise.
(Target_i386::Relocate::relocate): Likewise.
(Target_i386::Relocatable_size_for_reloc): Add R_386_IRELATIVE to
switch.
* x86_64.cc (class Output_data_plt_x86_64): Update declarations.
(Target_x86_64::do_plt_section_for_global): New function.
(Target_x86_64::do_plt_section_for_local): New function.
(Output_data_plt_x86_64::Output_data_plt_x86_64): Add symtab
parameter; change all callers. If doing a static link define
__rela_iplt_start and __rela_iplt_end.
(Output_data_plt_x86_64::add_entry): Handle IFUNC symbols.
(Output_data_plt_x86_64::add_local_ifunc_entry): New function.
(Target_x86_64::make_plt_section): Set sh_info field of .rel.plt
to point to .plt.
(Target_x86_64::make_local_ifunc_plt_entry): New function.
(Target_x86_64::Scan::check_non_pic): Add R_X86_64_IRELATIVE to
switch.
(Target_x86_64::Scan::reloc_needs_iplt_for_ifunc): New function.
(Target_x86_64::Scan::local): Handle IFUNC symbols. Add
R_X86_64_IRELATIVE to switch.
(Target_x86_64::Scan::global): Likewise.
(Target_x86_64::Relocate::relocate): Likewise.
(Target_x86_64::Relocatable_size_for_reloc): Add R_X86_64_IRELATIVE to
switch.
* target.h (class Target): Add plt_section_for_global and
plt_section_for_local functions. Add do_plt_section_for_global
and do_plt_section_for_local virtual functions.
* symtab.h (Symbol::needs_plt_entry): Handle IFUNC symbol. Add
clarifying comments.
(Symbol::use_plt_offset): Handle IFUNC symbol.
* object.cc (Sized_relobj::Sized_relobj): Initialize
local_plt_offsets_.
(Sized_relobj::local_has_plt_offset): New function.
(Sized_relobj::local_plt_offset): New function.
(Sized_relobj::set_local_plt_offset): New function.
(Sized_relobj::do_count): Handle IFUNC symbol.
* object.h (class Symbol_value): Add is_ifunc_symbol_ field. Take
a bit away from input_shndx_ field. Add set_is_func_symbol and
is_ifunc_symbol functions.
(class Sized_relobj): Update declarations. Remove Tls_got_entry
and Local_tls_got_offsets. Define Local_plt_offsets. Add
local_plt_offsets_ field.
(Sized_relobj::clear_local_symbols): Clear local_plt_offsets_.
* output.h (class Output_section_data): Add non-const
output_section function.
(class Output_data_got): Update declarations.
(class Output_data_got::Got_entry): Add use_plt_offset_ field.
Add use_plt_offset parameter to global and local constructors.
Change all callers. Change local_sym_index_ field to 31 bits.
Change GSYM_CODE and CONSTANT_CODE accordingly.
* output.cc (Output_data_reloc_base::do_adjust_output_section): If
doing a static link don't set sh_link field.
(Output_data_got::Got_entry::write): Use PLT offset if
appropriate.
(Output_data_got::add_global_plt): New function.
(Output_data_got::add_local_plt): New function.
* target-reloc.h (relocate_section): Handle IFUNC symbol.
* defstd.cc (in_section): Remove entries for __rel_iplt_start,
__rel_iplt_end, __rela_iplt_start, and __rela_iplt_end.
* configure.ac: Set IFUNC automake conditional for glibc >= 2.11.
* testsuite/Makefile.am: Add a bunch of IFUNC tests, all within
IFUNC conditional.
* testsuite/ifunc-sel.h: New file.
* testsuite/ifuncmain1.c: New file.
* testsuite/ifuncmain1vis.c: New file.
* testsuite/ifuncmod1.c: New file.
* testsuite/ifuncdep2.c: New file.
* testsuite/ifuncmain2.c: New file.
* testsuite/ifuncmain3.c: New file.
* testsuite/ifuncmod3.c: New file.
* testsuite/ifuncmain4.c: New file.
* testsuite/ifuncmain5.c: New file.
* testsuite/ifuncmod5.c: New file.
* testsuite/ifuncmain6pie.c: New file.
* testsuite/ifuncmod6.c: New file.
* testsuite/ifuncmain7.c: New file.
* configure, testsuite/Makefile.in: Rebuild.
H.J. Lu