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H.J. Lu f604c2a2a5 i386: Improve PLT generation and synthetic PLT symbols
On i386, the procedure linkage table (PLT) is used to

1. Call external function.
2. Call internal IFUNC function.  The best implementation is selected
for the target processor at run-time.
3. Act as the canonical function address.
4. Support LD_AUDIT to audit external function calls.
5. Support LD_PROFILE to profile external function calls.

PLT looks like:

PLT0:  push  GOT[1]
       jmp   *GOT[2]
       nop
PLT1:  jmp   *GOT[name1_index]
       push  name1_reloc_index
       jmp   PLT0

GOT is an array of addresses.  Initially the GOT entry of name1 is
filled with the address of the "push name1_reloc_index" instruction.
The function, name1, is called via "jmp *GOT[name1]" in the PLT entry.
Even when lazy binding is disabled by "-z now", the PLT0 entry may
still be used with LD_AUDIT or LD_PROFILE if PLT entry is used for
canonical function address.

1. With lazy binding, when the external function, name1, is called the
first time, dynamic linker is called via PLT0 to update GOT[name1_index]
with the actual address of name1 and transfers control to name1
afterwards.
2. PLT is also used to call a local IFUNC function, name1, run-time
loader updates GOT[name1_index] when loading the module.

This patch

1. Remove PLT layout configurations from i386 backend_data.
2. Add generic, lay and non-lazy PLT layout configurations to i386
link_hash_table.  Generic PLT layout includes the PLT entry templates,
information how to update the first instruction in PLT and PLT eh_frame
informaton, which are initialized in i386 setup_gnu_properties, based
on PIC and target selection.  PLT section alignment is also set to PLT
entry size for non-NaCl/VxWorks target.
3. Remove elf_i386_create_dynamic_sections.  create_dynamic_sections
isn't always called, but GOT relocations need GOT relocations.  Instead,
create all i386 specific dynamic sections in i386 setup_gnu_properties,
which initializes elf.dynobj, so that i386 check_relocs can be simplified.
4. Rewrite elf_i386_get_synthetic_symtab to check PLT sections against
all dynamic relocations to support both lazy and non-lazy PLTs.

bfd/

	* elf32-i386.c (PLT_ENTRY_SIZE): Renamed to ...
	(LAZY_PLT_ENTRY_SIZE): This.
	(NON_LAZY_PLT_ENTRY_SIZE): New.
	(elf_i386_plt0_entry): Renamed to ...
	(elf_i386_lazy_plt0_entry): This.
	(elf_i386_plt_entry): Renamed to ...
	(elf_i386_lazy_plt_entry): This.
	(elf_i386_pic_plt0_entry): Renamed to ...
	(elf_i386_pic_lazy_plt0_entry): This.
	(elf_i386_pic_plt_entry): Renamed to ...
	(elf_i386_pic_lazy_plt_entry): This.
	(elf_i386_got_plt_entry): Renamed to ...
	(elf_i386_non_lazy_plt_entry): This.
	(elf_i386_pic_got_plt_entry): Renamed to ...
	(elf_i386_pic_non_lazy_plt_entry): This.
	(elf_i386_eh_frame_plt): Renamed to ...
	(elf_i386_eh_frame_lazy_plt): This.
	(elf_i386_eh_frame_plt_got): Renamed to ...
	(elf_i386_eh_frame_non_lazy_plt): This.
	(elf_i386_plt_layout): Renamed to ...
	(elf_i386_lazy_plt_layout): This.  Remove eh_frame_plt_got and
	eh_frame_plt_got_size.
	(elf_i386_non_lazy_plt_layout): New.
	(elf_i386_plt_layout): Likewise.
	(elf_i386_non_lazy_plt): Likewise.
	(GET_PLT_ENTRY_SIZE): Removed.
	(elf_i386_plt): Renamed to ...
	(elf_i386_lazy_plt): This.
	(elf_i386_backend_data): Remove plt.  Rename is_vxworks to os.
	(elf_i386_arch_bed): Updated.
	(elf_i386_link_hash_table): Add plt, lazy_plt and non_lazy_plt.
	(elf_i386_create_dynamic_sections): Removed.
	(elf_i386_check_relocs): Don't check elf.dynobj.  Don't call
	_bfd_elf_create_ifunc_sections nor _bfd_elf_create_got_section.
	(elf_i386_adjust_dynamic_symbol): Updated.
	(elf_i386_allocate_dynrelocs): Updated.  Pass 0 as PLT header
	size to _bfd_elf_allocate_ifunc_dyn_relocs and don't allocate
	size for PLT0 if there is no PLT0.
	(elf_i386_size_dynamic_sections): Updated.  Check whether GOT
	output section is discarded only if GOT isn't empty.
	(elf_i386_relocate_section): Updated.  Properly get PLT index
	if there is no PLT0.
	(elf_i386_finish_dynamic_symbol): Updated.  Don't fill the
	second and third slots in the PLT entry if there is no PLT0.
	(elf_i386_finish_dynamic_sections): Updated.  Don't fill PLT0
	if there is no PLT0.  Set sh_entsize on the .plt.got section.
	(elf_i386_nacl_plt): Forward declaration.
	(elf_i386_get_plt_sym_val): Removed.
	(elf_i386_get_synthetic_symtab): Rewrite to check PLT sections
	against all dynamic relocations.
	(elf_i386_link_setup_gnu_properties): New function.
	(elf_backend_create_dynamic_sections): Updated.
	(elf_backend_setup_gnu_properties): New.
	(elf_i386_nacl_plt): Updated.
	(elf_i386_nacl_arch_bed): Likewise.
	(elf_i386_vxworks_arch_bed): Likewise.

ld/

	* testsuite/ld-i386/i386.exp: Add some -z now tests.
	* testsuite/ld-i386/plt-pic2.dd: New file.
	* testsuite/ld-i386/plt2.dd: Likewise.
	* testsuite/ld-i386/plt2.rd: Likewise.
	* testsuite/ld-i386/plt2.s: Likewise.
	* testsuite/ld-ifunc/ifunc-16-i386-now.d: Likewise.
	* testsuite/ld-ifunc/ifunc-2-i386-now.d: Likewise.
	* testsuite/ld-ifunc/ifunc-2-local-i386-now.d: Likewise.
	* testsuite/ld-ifunc/pr17154-i386-now.d: Likewise.
	* testsuite/ld-i386/pr20830.d: Update the .plt.got section
	with func@plt.
2017-05-08 10:11:32 -07:00
bfd i386: Improve PLT generation and synthetic PLT symbols 2017-05-08 10:11:32 -07:00
binutils Cast relcount to unsigned long when comparing with sec->reloc_count 2017-05-02 12:16:26 -07:00
config picflag.m4 high bit set in comment 2017-01-05 00:02:57 +10:30
cpu Update the openrisc previous program counter (ppc) when running code in the cgen based simulator. 2017-03-20 15:33:51 +00:00
elfcpp Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
etc update-copyright.py for binutils 2017-01-05 00:03:07 +10:30
gas MIPS16/GAS: Relax 32-bit non-PIC PC-relative synthetic instructions 2017-05-03 20:47:40 +01:00
gdb Remove some uses of MAX_REGISTER_SIZE from mips-tdep.c 2017-05-08 09:40:07 +01:00
gold [GOLD] testsuite/plugin_section_order.c fix 2017-04-27 11:54:29 +09:30
gprof Update year range in copyright notice of all files. 2017-01-02 14:08:56 +10:30
include Handle symbol defined in IR and referenced in DSO 2017-04-20 07:48:35 -07:00
intl
ld i386: Improve PLT generation and synthetic PLT symbols 2017-05-08 10:11:32 -07:00
libdecnumber
libiberty cplus_demangle_fill_component: Handle DEMANGLE_COMPONENT_RVALUE_REFERENCE 2017-03-27 14:18:41 +01:00
opcodes RISC-V: Fix disassemble for c.li, c.andi and c.addiw 2017-05-04 03:20:30 -07:00
readline Improve MinGW support in Readline 2016-09-17 11:50:37 +03:00
sim Fix ldn/stn multiple instructions. Fix testcases with unaligned data. 2017-04-22 16:36:01 -07:00
texinfo
zlib Sync ZLIB with FSF GCC sources, bringing in version 1.2.11. 2017-02-20 12:52:22 +00:00
.cvsignore
.gitattributes Add a .gitattributes file for use with git-merge-changelog 2014-07-25 18:07:23 -04:00
.gitignore Add archives and make stamps to the .gitignore file. 2016-09-27 15:10:42 +01:00
ChangeLog * config.sub: Sync with master version in config project. 2017-04-13 02:34:19 -07:00
compile
config-ml.in
config.guess Sync top level config files with master versions in the FSF config project. 2017-03-22 14:01:03 +00:00
config.rpath
config.sub * config.sub: Sync with master version in config project. 2017-04-13 02:34:19 -07:00
configure Sync top-level make and configure files with FSF GCC mainline versions. 2017-01-23 11:55:48 +00:00
configure.ac Sync top-level make and configure files with FSF GCC mainline versions. 2017-01-23 11:55:48 +00:00
COPYING
COPYING3
COPYING3.LIB
COPYING.LIB
COPYING.LIBGLOSS 2013-01-07 Jeff Johnston <jjohnstn@redhat.com> 2013-01-07 21:39:26 +00:00
COPYING.NEWLIB
depcomp
djunpack.bat
install-sh
libtool.m4
lt~obsolete.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
MAINTAINERS
Makefile.def Sync top-level make and configure files with FSF GCC mainline versions. 2017-01-23 11:55:48 +00:00
Makefile.in Sync top-level make and configure files with FSF GCC mainline versions. 2017-01-23 11:55:48 +00:00
Makefile.tpl Sync top-level make and configure files with FSF GCC mainline versions. 2017-01-23 11:55:48 +00:00
makefile.vms
missing
mkdep
mkinstalldirs
move-if-change
README
README-maintainer-mode
setup.com
src-release.sh
symlink-tree 2005-07-14 Kelley Cook <kcook@gcc.gnu.org> 2005-07-14 01:24:56 +00:00
ylwrap

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

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then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
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If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
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