binutils-gdb/ld
Alan Modra 9e390558ce PowerPC PLT stub tidy
This is in preparation for the next patch adding Spectre variant 2
mitigation for PowerPC and PowerPC64.  Besides tidying code involved
in stub output (to reduce the number of places where bctr is output),
the patch adds some user visible features:

1) PowerPC64 ELFv2 global entry stubs now are aligned under the
   control of --plt-align, with a default alignment of 32 bytes.
2) PowerPC64 __glink_PLTresolve is no longer padded out with nops.
3) PowerPC32 PLT stubs are aligned under the control of --plt-align,
   with the default alignment being 16 bytes as before.
4) The PowerPC32 branch/nop table emitted before __glink_PLTresolve
   is now smaller in many cases.  It was sized incorrectly when the
   __tls_get_addr_opt stub was used, and unnecessarily included space
   for local ifuncs.

bfd/
	* elf32-ppc.c (GLINK_ENTRY_SIZE): Add parameters, handle
	__tls_get_addr_opt, and alignment sizing.
	(TLS_GET_ADDR_GLINK_SIZE): Delete.
	(is_nonpic_glink_stub): Don't use GLINK_ENTRY_SIZE.
	(ppc_elf_get_synthetic_symtab): Recognize stubs spaced at 4, 6,
	or 8 insns.
	(ppc_elf_link_hash_table_create): Init new ppc_elf_params field.
	(allocate_dynrelocs): Use new GLINK_ENTRY_SIZE.
	(ppc_elf_size_dynamic_sections): Likewise.  Size branch table
	by PLT reloc count.
	(write_glink_stub): Handle __tls_get_addr_opt stub.
	Pad out to size given by GLINK_ENTRY_SIZE.
	(ppc_elf_relocate_section): Adjust write_glink_stub call.
	(ppc_elf_finish_dynamic_symbol): Likewise.
	(ppc_elf_finish_dynamic_sections): Write PLTresolve without using
	insn array since so many need rewriting.
	* elf32-ppc.h (struct ppc_elf_params): Add plt_stub_align.
	* elf64-ppc.c (GLINK_PLTRESOLVE_SIZE): Rename from
	GLINK_CALL_STUB_SIZE.  Add htab param and evaluate to size without
	nops.  Adjust all uses.
	(ppc64_elf_get_synthetic_symtab): Don't use GLINK_CALL_STUB_SIZE
	in glink_vma calculation.
	(struct ppc_link_hash_table): Add global_entry section pointer.
	(create_linkage_sections): Create separate section for global
	entry stubs.
	(PPC_LO, PPC_HI, PPC_HA): Move earlier.
	(size_global_entry_stubs): Handle sizing for aligned stubs.
	(ppc64_elf_size_dynamic_sections): Handle global_entry alloc,
	and don't stash end of glink branch table in rawsize.
	(ppc_build_one_stub): Rewrite stub size calculations.
	(build_global_entry_stubs): Use new section.
	(ppc64_elf_build_stubs): Don't pad __glink_PLTresolve with nops.
	Build lazy link stubs out to end of section.  Build global entry
	stubs in new section.
gold/
	* options.h (plt_align): Support for PowerPC32 too.
	* powerpc.cc (Stub_table::stub_align): Heed --plt-align for 32-bit.
	(Stub_table::plt_call_size, branch_stub_size): Tidy.
	(Stub_table::plt_call_align): Implement using stub_align.
	(Output_data_glink::global_entry_align): New function.
	(Output_data_glink::global_entry_off): New function.
	(Output_data_glink::global_entry_address): Use global_entry_off.
	(Output_data_glink::pltresolve_size): New function, replacing
	pltresolve_size_ constant.  Update all uses.
	(Output_data_glink::add_global_entry): Align offset.
	(Output_data_glink::set_final_data_size): Use global_entry_align.
	(Stub_table::do_write): Don't pad __glink_PLTrelsolve with nops.
	Tidy stub output.  Use global_entry_off.
ld/
	* emultempl/ppc32elf.em (params): Init new field.
	(enum ppc32_opt): New enum to define OPTION_* values.  Add
	OPTION_PLT_ALIGN and OPTION_NO_PLT_ALIGN.
	(PARSE_AND_LIST_LONGOPTS): Handle new options.
	(PARSE_AND_LIST_ARGS_CASES): Likewise.
	(PARSE_AND_LIST_OPTIONS): Likewise.  Break up help output.
	* emultempl/ppc64elf.em (ppc_add_stub_section): Init alignment
	correctly for negative --plt-stub-align.
	* testsuite/ld-powerpc/elfv2exe.d,
	* testsuite/ld-powerpc/elfv2so.d,
	* testsuite/ld-powerpc/relbrlt.d,
	* testsuite/ld-powerpc/relbrlt.s,
	* testsuite/ld-powerpc/tlsexe.d,
	* testsuite/ld-powerpc/tlsexe.r,
	* testsuite/ld-powerpc/tlsexe32.d,
	* testsuite/ld-powerpc/tlsexe32.g,
	* testsuite/ld-powerpc/tlsexe32.r,
	* testsuite/ld-powerpc/tlsexetoc.d,
	* testsuite/ld-powerpc/tlsexetoc.r,
	* testsuite/ld-powerpc/tlsopt5_32.d,
	* testsuite/ld-powerpc/tlsso.d,
	* testsuite/ld-powerpc/tlstocso.d: Update for changed stub order.
2018-01-17 18:51:04 +10:30
..
emulparams RISC-V: Disable shared library support for embedded elf. 2018-01-05 14:29:49 -08:00
emultempl PowerPC PLT stub tidy 2018-01-17 18:51:04 +10:30
po Update translations for various binutils components. 2018-01-16 12:45:44 +00:00
scripttempl ld: Add "-z separate-code" option to ELF linker 2018-01-11 19:01:52 -08:00
testsuite PowerPC PLT stub tidy 2018-01-17 18:51:04 +10:30
.gitignore
aclocal.m4
ChangeLog PowerPC PLT stub tidy 2018-01-17 18:51:04 +10:30
ChangeLog-0001
ChangeLog-0203
ChangeLog-2004
ChangeLog-2005
ChangeLog-2006
ChangeLog-2007
ChangeLog-2008
ChangeLog-2009
ChangeLog-2010
ChangeLog-2011
ChangeLog-2012
ChangeLog-2013
ChangeLog-2014
ChangeLog-2015
ChangeLog-2016
ChangeLog-2017 ChangeLog rotation 2018-01-03 17:49:42 +10:30
ChangeLog-9197
ChangeLog-9899
config.in Add configure flag to enable gnu hash style by default. 2017-08-08 07:25:39 +09:30
configure Bump version number to 2.30.51 2018-01-13 13:31:12 +00:00
configure.ac Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
configure.host Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
configure.tgt Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
deffile.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
deffilep.y Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
dep-in.sed
elf-hints-local.h
fdl.texi
gen-doc.texi Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
genscrba.sh
genscripts.sh ld: Add "-z separate-code" option to ELF linker 2018-01-11 19:01:52 -08:00
h8-doc.texi Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ld.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ld.texinfo Add -z undefs option to the ELF linker. 2018-01-12 08:15:55 +00:00
ldbuildid.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldbuildid.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldcref.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldctor.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldctor.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldemul.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldemul.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldexp.c ld: Remove unused expression state 2018-01-11 17:35:35 +00:00
ldexp.h ld: Remove unused expression state 2018-01-11 17:35:35 +00:00
ldfile.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldfile.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldgram.y Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldint.texinfo Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldlang.c ld: Fix issue where PROVIDE overrides defined symbol 2018-01-11 17:35:35 +00:00
ldlang.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldlex-wrapper.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldlex.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldlex.l Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldmain.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldmain.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldmisc.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldmisc.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldver.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldver.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldwrite.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
ldwrite.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
lexsup.c ld: Add "-z separate-code" option to ELF linker 2018-01-11 19:01:52 -08:00
MAINTAINERS Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
Makefile.am Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
Makefile.in Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
mri.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
mri.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
NEWS Add 2.30 markers to NEWS files. 2018-01-13 13:20:55 +00:00
pe-dll.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
pe-dll.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
pep-dll.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
pep-dll.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
plugin.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
plugin.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
README Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
stamp-h.in
sysdep.h Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
testplug2.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
testplug3.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
testplug4.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
testplug.c Update year range in copyright notice of binutils files 2018-01-03 17:49:56 +10:30
TODO

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		README for LD

This is the GNU linker.  It is distributed with other "binary
utilities" which should be in ../binutils.  See ../binutils/README for
more general notes, including where to send bug reports.

There are many features of the linker:

* The linker uses a Binary File Descriptor library (../bfd)
  that it uses to read and write object files.  This helps
  insulate the linker itself from the format of object files.

* The linker supports a number of different object file
  formats.  It can even handle multiple formats at once:
  Read two input formats and write a third.

* The linker can be configured for cross-linking.

* The linker supports a control language.

* There is a user manual (ld.texinfo), as well as the
  beginnings of an internals manual (ldint.texinfo).

Installation
============

See ../binutils/README.

If you want to make a cross-linker, you may want to specify
a different search path of -lfoo libraries than the default.
You can do this by setting the LIB_PATH variable in ./Makefile
or using the --with-lib-path configure switch.

To build just the linker, make the target all-ld from the top level
directory (one directory above this one).

Porting to a new target
=======================

See the ldint.texinfo manual.

Reporting bugs etc
===========================

See ../binutils/README.

Known problems
==============

The Solaris linker normally exports all dynamic symbols from an
executable.  The GNU linker does not do this by default.  This is
because the GNU linker tries to present the same interface for all
similar targets (in this case, all native ELF targets).  This does not
matter for normal programs, but it can make a difference for programs
which try to dlopen an executable, such as PERL or Tcl.  You can make
the GNU linker export all dynamic symbols with the -E or
--export-dynamic command line option.

HP/UX 9.01 has a shell bug that causes the linker scripts to be
generated incorrectly.  The symptom of this appears to be "fatal error
- scanner input buffer overflow" error messages.  There are various
workarounds to this:
  * Build and install bash, and build with "make SHELL=bash".
  * Update to a version of HP/UX with a working shell (e.g., 9.05).
  * Replace "(. ${srcdir}/scripttempl/${SCRIPT_NAME}.sc)" in
    genscripts.sh with "sh ${srcdir}..." (no parens) and make sure the
    emulparams script used exports any shell variables it sets.

Copyright (C) 2012-2018 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.