Commit graph

10989 commits

Author SHA1 Message Date
Tristan Gingold
fbe383b9ee mach-o: handle lasz load dylib command.
bfd/
	* mach-o.c (bfd_mach_o_read_dylib): Handle lazy load dylib.
	(bfd_mach_o_read_command): Ditto.

binutils/
	* od-macho.c (dump_load_command): Handle lazy load dylib.
2014-03-17 10:14:23 +01:00
Alan Modra
49f2e27ce4 daily update 2014-03-17 09:30:41 +10:30
Alan Modra
c296d686ed daily update 2014-03-16 09:30:42 +10:30
Alan Modra
2b8118237a daily update 2014-03-15 09:30:57 +10:30
Nick Clifton
5a026fc9a2 Fix build time problem with MingGW hosts, which do not have a strnlen() function.
2014-03-13  Meador Inge  <meadori@codesourcery.com>

	 * configure.in: Add strnlen to AC_CHECK_DECLS.
	 * config.in: Regenerate.
         * configure: Regenerate.
	 * sysdep.h (strnlen): Add prototype.

         * dwarf.c (strnlen): Move prototype ...
	 * sysdep.h (strnlen): ... to here.
2014-03-14 11:21:00 +00:00
Alan Modra
c3301df1da Fix overflow handling of VLE_SDA21
bfd/
	* elf32-ppc.c (ppc_elf_relocate_section): Correct overflow
	handling for VLE_SDA21 relocs.
ld/testsuite/
	* ld-powerpc/vle.ld: Place .PPC.EMB.sdata0 within 32k of 0.
	* ld-powerpc/vle-reloc-3.d: Update.
2014-03-14 15:01:53 +10:30
Alan Modra
221c28ecea daily update 2014-03-14 09:31:24 +10:30
Tristan Gingold
167ad85bf0 Add pe/x86_64 bigobj file format.
bfd/
	* peicode.h (pe_ILF_object_p): Adjust, as the version number
	has been read.
	(pe_bfd_object_p): Also read version number to detect ILF.
	* pe-x86_64.c (COFF_WITH_PE_BIGOBJ): Define.
	(x86_64pe_bigobj_vec): Define
	* coffcode.h (bfd_coff_backend_data): Add _bfd_coff_max_nscns field.
	(bfd_coff_max_nscns): New macro.
	(coff_compute_section_file_positions): Use unsigned int for
	target_index.  Compare with bfd_coff_max_nscns.
	(bfd_coff_std_swap_table, ticoff0_swap_table, ticoff1_swap_table):
	Set a value for _bfd_coff_max_nscns.
	(header_bigobj_classid): New constant.
	(coff_bigobj_swap_filehdr_in, coff_bigobj_swap_filehdr_out)
	(coff_bigobj_swap_sym_in, coff_bigobj_swap_sym_out)
	(coff_bigobj_swap_aux_in, coff_bigobj_swap_aux_out): New
	functions.
	(bigobj_swap_table): New table.
	* libcoff.h: Regenerate.
	* coff-sh.c (bfd_coff_small_swap_table): Likewise.
	* coff-alpha.c (alpha_ecoff_backend_data): Add value for
	_bfd_coff_max_nscns.
	* coff-mips.c (mips_ecoff_backend_data): Likewise.
	* coff-rs6000.c (bfd_xcoff_backend_data)
	(bfd_pmac_xcoff_backend_data): Likewise.
	* coff64-rs6000.c (bfd_xcoff_backend_data)
	(bfd_xcoff_aix5_backend_data): Likewise.
	* targets.c (x86_64pe_bigobj_vec): Declare.
	* configure.in (x86_64pe_bigobj_vec): New vector.
	* configure: Regenerate.
	* config.bfd: Add bigobj object format for Windows targets.

gas/
	* config/tc-i386.c (use_big_obj): Declare.
	(OPTION_MBIG_OBJ): Define.
	(md_longopts): Add -mbig-obj option.
	(md_parse_option): Handle it.
	(md_show_usage): Display help for this option.
	(i386_target_format): Use bigobj for x86-64 if -mbig-obj.
	* doc/c-i386.texi: Document the option.

gas/testsuite/
	* gas/pe/big-obj.d, gas/pe/big-obj.s: Add test.
	* gas/pe/pe.exp: Add test.

include/coff/
	* pe.h (struct external_ANON_OBJECT_HEADER_BIGOBJ): Declare.
	(FILHSZ_BIGOBJ): Define.
	(struct external_SYMBOL_EX): Declare.
	(SYMENT_BIGOBJ, SYMESZ_BIGOBJ): Define.
	(union external_AUX_SYMBOL_EX): Declare.
	(AUXENT_BIGOBJ, AUXESZ_BIGOBJ): Define.
	* internal.h (struct internal_filehdr): Change type
	of f_nscns.
2014-03-13 09:33:07 +01:00
Alan Modra
0021d171fa daily update 2014-03-13 09:31:14 +10:30
Nick Clifton
c792917cdc Prevent the linker from generaing a seg-fault when the user attempts to link
an ARM ELF binary into an AARCH64 ELF executable.

	PR ld/16671
	* elf32-arm.c (elf32_arm_add_symbol_hook): Check for ARM format
	before testing for vxworks.
2014-03-12 13:12:37 +00:00
Pedro Alves
5893c83a47 Mention PR gdb/16696 in corresponding ChangeLog entry. 2014-03-12 11:07:37 +00:00
Alan Modra
fa47fa9246 autoreconf
Regenerate Makefile.in in bfd, binutils, gas, gold, gprof, ld, opcodes.
Regenerate gas/config.in.
2014-03-12 15:02:00 +10:30
Alan Modra
bbefd0a926 objcopy/strip ELF program header p_vaddr confusion
copy_elf_program_header has logic to reject non-alloc sections when
calculating p_vaddr offset for padding, but blithely assumed the
first section in a segment was allocated.

	PR 16690
	* elf.c (copy_elf_program_header): Ignore first section lma if
	non-alloc.
2014-03-12 10:33:26 +10:30
Alan Modra
32ed590d7e daily update 2014-03-12 09:31:13 +10:30
Alan Modra
3c865fca87 intptr_t type definition needed
coffcode.h uses an intptr_t cast inside an #ifdef RS6000COFF_C, so
ensure that intptr_t is defined.  We don't see this when
cross-compiling from linux due to intptr_t being provided by
unistd.h.

	PR 16686
	* coff-rs6000.c: Include stdint.h.
	* coff64-rs6000.c: Likewise.
2014-03-11 16:13:45 +10:30
Alan Modra
61d1ce24e8 daily update 2014-03-11 09:30:40 +10:30
Tristan Gingold
ce15efd88c Remove bfd/ticoff.h (unused)
2013-12-03  Tristan Gingold  <gingold@adacore.com>

	* ticoff.h: Remove.
2014-03-10 15:11:06 +01:00
Alan Modra
592fdf42ef daily update 2014-03-10 09:30:41 +10:30
Alan Modra
c5cec84eb3 daily update 2014-03-09 09:31:12 +10:30
Alan Modra
86c9573369 Better overflow checking for powerpc32 relocations
Similar to the powerpc64 patch, this improves overflow checking in
elf32-ppc.c.  Many reloc "howto" entries needed fixes, some just
cosmetic.

The patch also fixes the R_PPC_VLE_SDA21 reloc application code, which
was horribly broken.  In fact, it may still be broken since Power ISA
2.07 says e_li behaves as
   RT <- EXTS(li20 1:4 || li20 5:8 || li20 0 || li20 9:19)
where li20 is a field taken from bits 17..20, 11..15, 21..31 of the
instruction.  Freescale VLEPEM says differently, and I assume
correctly, that
   RT <- EXTS(li20 0:3 || li20 4:8 || li20 9:19)
The VLE_SDA21 relocation description matches this too.

Now the VLE_SDA21 relocation specifies in the case where e_addi16 is
converted to e_li for symbols in .PPC.EMB.sdata0 or .PPC.EMB.sbss0
(no base register), that the field is restricted to 16 bits, with the
sign bit being propagated to the top 4 bits.  I don't see the sense in
restricting the value like this, so have allowed the full 20 bit
signed value.  This of course is compatible with the reloc description
in that values in the 16 bit signed range will result in exactly the
same insn field as when the reloc description is followed to the
letter.

	* elf32-ppc.c (ppc_elf_howto_raw): Correct overflow check for
	many relocations.  Correct bitsize and rightshift too for a number
	of VLE relocs.  Describe R_PPC_VLE_SDA21 and R_PPC_VLE_SDA21_LO.
	Correct dst_mask on R_PPC_VLE_SDA21_LO.
	(ppc_elf_vle_split16): Tidy, delete unnecessary prototype.
	(ppc_elf_relocate_section): Modify overflow test for 16-bit
	fields in instructions to signed/unsigned according to whether
	the field takes a signed or unsigned value.  Tidy vle split16 code.
	Correct R_PPC_VLE_SDA21 and R_PPC_VLE_SDA21_LO handling.
2014-03-08 16:30:43 +10:30
Alan Modra
b80eed39e2 Better overflow checking for powerpc64 relocations
R_PPC64_ADDR16 is used in three contexts:
- .short data relocation
- 16-bit signed insn fields, eg. addi
- 16-bit unsigned insn fields, eg. ori
In the first case we want to allow both signed and unsigned 16-bit
values, the latter two ought to error if the field exceeds the range
of values allowed for 16-bit signed and unsigned integers
respectively.  These conflicting requirements meant that ld had to
choose the least restrictive overflow checks, and thus it is possible
to construct testcases where an addi field overflows but is not
reported by ld.  Many relocations dealing with 16-bit insn fields have
this problem.  What's more, some relocations that are only ever used
for signed fields of instructions woodenly copied the lax overflow
checking of R_PPC64_ADDR16.

bfd/
	* elf64-ppc.c (ppc64_elf_howto_raw): Use complain_overflow_signed
	for R_PPC64_ADDR14, R_PPC64_ADDR14_BRTAKEN, R_PPC64_ADDR14_BRNTAKEN,
	R_PPC64_SECTOFF, R_PPC64_ADDR16_DS, R_PPC64_SECTOFF_DS,
	R_PPC64_REL16 entries.  Use complain_overflow_dont for R_PPC64_TOC.
	(ppc64_elf_relocate_section): Modify overflow test for 16-bit
	fields in instructions to signed/unsigned according to whether
	the field takes a signed or unsigned value.
gold/
	* powerpc.cc (Powerpc_relocate_functions::Overflow_check): Add
	CHECK_UNSIGNED, CHECK_LOW_INSN, CHECK_HIGH_INSN.
	(Powerpc_relocate_functions::has_overflow_unsigned): New function.
	(Powerpc_relocate_functions::has_overflow_bitfield,
	overflowed): Use the above.
	(Target_powerpc::Relocate::relocate): Correct overflow checking
	for a number of relocations.  Modify overflow test for 16-bit
	fields in instructions to signed/unsigned according to whether
	the field takes a signed or unsigned value.
2014-03-08 12:57:58 +10:30
Alan Modra
2ba229e2c9 daily update 2014-03-08 09:30:39 +10:30
Pedro Alves
c38e85596e AIX 32-bit core loading, high section addresses.
I noticed GDB was failing to enable threading support for 32-bit AIX
cores.  I traced it to failure to read variables from libpthreads.a.
The issue is that data for that library is loaded at a high address,
and bfd is sign extending the section addresses:

 (gdb) info files
 Symbols from "/home/palves/crash".
 Local core dump file:
	 `/home/palves/core', file type aixcoff-rs6000.
	 0x2ff22000 - 0x2ff23000 is .stack
	 0x20000000 - 0x200316e0 is .data
	 0x20000e90 - 0x200016c0 is .data
	 0xfffffffff0254000 - 0xfffffffff0297920 is .data
	 0xfffffffff07b46a8 - 0xfffffffff07b47c8 is .data
	 0xfffffffff0298000 - 0xfffffffff029bfcc is .data
	 0xfffffffff06dafe0 - 0xfffffffff07b3838 is .data
 Local exec file:
	 `/home/palves/crash', file type aixcoff-rs6000.
	 Entry point: 0x20001394
	 0x10000150 - 0x10000e90 is .text
	 0x20000e90 - 0x2000149c is .data
	 0x2000149c - 0x200016c0 is .bss
	 0xd053b124 - 0xd053e15f is .text in /usr/lib/libpthreads.a(shr_comm.o)
	 0xf0254000 - 0xf0297920 is .data in /usr/lib/libpthreads.a(shr_comm.o)
	 0xf0254450 - 0xf0297920 is .bss in /usr/lib/libpthreads.a(shr_comm.o)
	 0xd053a280 - 0xd053aabe is .text in /usr/lib/libcrypt.a(shr.o)
	 0xf07b46a8 - 0xf07b47c8 is .data in /usr/lib/libcrypt.a(shr.o)
	 0xf07b47c8 - 0xf07b47c8 is .bss in /usr/lib/libcrypt.a(shr.o)
	 0xd04fb180 - 0xd053917e is .text in /usr/lib/libpthreads.a(shr_xpg5.o)
	 0xf0298000 - 0xf029bfcc is .data in /usr/lib/libpthreads.a(shr_xpg5.o)
	 0xf029bf64 - 0xf029bfcc is .bss in /usr/lib/libpthreads.a(shr_xpg5.o)
	 0xd0100900 - 0xd04fa39c is .text in /usr/lib/libc.a(shr.o)
	 0xf06dafe0 - 0xf07b3838 is .data in /usr/lib/libc.a(shr.o)
	 0xf0751e94 - 0xf07b3838 is .bss in /usr/lib/libc.a(shr.o)

Notice:
	...
	0xfffffffff0298000 - 0xfffffffff029bfcc is .data
	...

Those are the bfd section start/end addresses.  It't not visible here:

         ...
	 0xf0298000 - 0xf029bfcc is .data in /usr/lib/libpthreads.a(shr_xpg5.o)
         ...

... just because GDB trims that number to 32-bit when printing.

GDB then fails to find the memory for libpthreads.a variables in the
core, and falls back to reading it directly from the executable (which
yields the values as originally initialized in the code).

E.g.:

 (gdb) p &__n_pthreads
 $2 = (<data variable, no debug info> *) 0xf074fda8 <__n_pthreads>
 (gdb) p __n_pthreads
 $1 = -1

That should have returned 2 instead of -1.

bfd/
2014-03-07  Pedro Alves  <palves@redhat.com>

	* rs6000-core.c (rs6000coff_core_p): Cast pointers to bfd_vma
	through ptr_to_uint instead of through long.
2014-03-07 12:11:40 +00:00
Alan Modra
d598a9c177 daily update 2014-03-07 09:30:46 +10:30
Nick Clifton
e9847026c9 Patch for PR binutils/16664 which triggers a seg-fault when attempting to
display the contents of a corrupt attribute section.

	* readelf.c (process_attributes): Add checks for corrupt
	attribute section names.

	* elf-attrs.c (_bfd_elf_parse_attributes): Add checks for corrupt
	attribute section names.
2014-03-06 10:57:13 +00:00
Alan Modra
9e43f3e57d daily update 2014-03-06 09:31:23 +10:30
Alan Modra
4b95cf5c0c Update copyright years 2014-03-05 22:16:15 +10:30
Alan Modra
45965137be Support R_PPC64_ADDR64_LOCAL
This adds support for "func@localentry", an expression that returns the
ELFv2 local entry point address of function "func".  I've excluded
dynamic relocation support because that obviously would require glibc
changes.

include/elf/
	* ppc64.h (R_PPC64_REL24_NOTOC, R_PPC64_ADDR64_LOCAL): Define.
bfd/
	* elf64-ppc.c (ppc64_elf_howto_raw): Add R_PPC64_ADDR64_LOCAL entry.
	(ppc64_elf_reloc_type_lookup): Support R_PPC64_ADDR64_LOCAL.
	(ppc64_elf_check_relocs): Likewise.
	(ppc64_elf_relocate_section): Likewise.
	* Add BFD_RELOC_PPC64_ADDR64_LOCAL.
	* bfd-in2.h: Regenerate.
	* libbfd.h: Regenerate.
gas/
	* config/tc-ppc.c (ppc_elf_suffix): Support @localentry.
	(md_apply_fix): Support R_PPC64_ADDR64_LOCAL.
ld/testsuite/
	* ld-powerpc/elfv2-2a.s, ld-powerpc/elfv2-2b.s: New files.
	* ld-powerpc/elfv2-2exe.d, ld-powerpc/elfv2-2so.d: New files.
	* ld-powerpc/powerpc.exp: Run new test.
elfcpp/
	* powerpc.h (R_PPC64_REL24_NOTOC, R_PPC64_ADDR64_LOCAL): Define.
gold/
	* powerpc.cc (Target_powerpc::Scan::local, global): Support
	R_PPC64_ADDR64_LOCAL.
	(Target_powerpc::Relocate::relocate): Likewise.
2014-03-05 19:57:39 +10:30
Alan Modra
cfa7ea2a96 daily update 2014-03-05 09:31:07 +10:30
Richard Sandiford
cd0c81e90f Fix changelog formatting in last commit -- sorry 2014-03-04 21:30:39 +00:00
Richard Sandiford
4ba154f579 bfd/
2014-02-04  Heiher <r@hev.cc>

	* elfxx-mips.c (mips_set_isa_flags): Use E_MIPS_ARCH_64R2 for
	Loongson-3A.
	(mips_mach_extensions): Make bfd_mach_mips_loongson_3a an
	extension of bfd_mach_mipsisa64r2.

opcodes/
2014-02-04  Heiher <r@hev.cc>

	* mips-dis.c (mips_arch_choices): Usee ISA_MIPS64R2 for Loongson-3A.

gas/
2014-02-04  Heiher <r@hev.cc>

	* config/tc-mips.c (mips_cpu_info_table): Use ISA_MIPS64R2 for
	Loongson-3A.
2014-03-04 21:18:02 +00:00
Nick Clifton
eed94f8f8e Install patch for PR ld/16017. This adds support for generating PLT entries
using Thumb2 instructions for those cores which do not support the ARM ISA.

	* elf32-arm.c (elf32_thumb2_plt0_entry): New array.
	(elf32_thumb2_plt_entry): New array.
	(elf32_arm_create_dynamic_sections): Set PLT entry sizes when
	using thumb2 based PLT.
	(elf32_arm_populate_plt_entry): Handle generating Thumb2 based PLT
	entries.
	(elf32_arm_final_link_relocate): Do not bias jumps to Thumb based
	PLT entries.
	(elf32_arm_finish_dynamic_sections): Handle creation of Thumb2
	based PLT 0-entry.
	(elf32_arm_output_plt_map_1): Handle creation of local symbols for
	Thumb2 based PLT 0-entry.
	(elf32_arm_output_arch_local_syms): Handle creation of local
	symbols for Thumb2 based PLT entries.
2014-03-04 15:25:53 +00:00
Alan Modra
f97a10f1dc daily update 2014-03-04 09:30:37 +10:30
Alan Modra
74cc2cc592 daily update 2014-03-03 09:30:42 +10:30
Alan Modra
8913591154 daily update 2014-03-02 09:30:37 +10:30
Alan Modra
7b3858e08a daily update 2014-03-01 09:31:08 +10:30
Alan Modra
9850436d9e Fix check_relocs/gc_sweep_hook mismatch
PR ld/16643
	* elflink.c (elf_gc_sweep): Call gc_sweep_hook for exactly
	the same conditions we called check_relocs.
2014-02-28 14:38:27 +10:30
Alan Modra
67496a9c13 daily update 2014-02-28 09:31:17 +10:30
Yuri Gribov
1db37fe627 This patch adds support for ARM PLT entries that support a full 32-bit offset range.
Enabled via the use of a new linker command line option: --long-plt.

	* bfd-in.h: Add export of bfd_elf32_arm_use_long_plt.
	* bfd-in2.h: Regenerate.
	* elf32-arm.c (elf32_arm_plt_entry_long): New array.
	(elf32_arm_link_hash_table_create): Set plt_entry_size to 16 if
	using long PLT entries.
	(bfd_elf32_arm_use_long_plt): New function.
	(elf32_arm_populate_plt_entry): Add support for long PLT entries.

	* emultempl/armelf.em (OPTION_LONG_PLT): Define.
	(PARSE_AND_LIST_LONGOPTS): Add long-plt.
	(PARSE_AND_LIST_OPTIONS): Likewise.
	(PARSE_AND_LIST_ARGS_CASES): Handle long-plt.
	* ld.texinfo: Document --long-plt.

	* ld-arm/long-plt-format.s: New test case.
	* ld-arm/long-plt-format.d: Expected disassembly.
	* ld-arm/arm-elf.exp: Run the new test.
2014-02-27 14:35:37 +00:00
Alan Modra
db434ba03e Fix ELF ppc32 targets that don't use ppc32elf.em
5446cbdf82 broke powerpc-lynxos,
powerpc-netware, powerpc-windiss and powerpc-vxworks.

bfd/
	* elf32-ppc.c (ppc_elf_link_hash_table_create): Provide default
	params for targets that don't use ppc32elf.em.
ld/
	* emulparams/elf32ppcvxworks.sh: Source plt_unwind.sh and
	use ppc32elf.em.
	* emultempl/ppc32elf.em (ppc_after_open): Don't compile for
	vxworks.
	(LDEMUL_AFTER_OPEN): Don't set for vxworks.
	(PARSE_AND_LIST_LONGOPTS, PARSE_AND_LIST_OPTIONS): Exclude
	-secure-plt, -bss-plt and -sdata-got when vxworks.
2014-02-27 23:39:01 +10:30
Alan Modra
2e877f5ecb daily update 2014-02-27 09:31:09 +10:30
Alan Modra
cad798bd0d daily update 2014-02-26 09:30:38 +10:30
Alan Modra
f91d941da8 daily update 2014-02-25 09:30:39 +10:30
Alan Modra
605a662f6a daily update 2014-02-24 09:30:35 +10:30
Alan Modra
cb5111bcea daily update 2014-02-23 09:30:37 +10:30
Alan Modra
b103660c45 daily update 2014-02-22 09:30:38 +10:30
Alan Modra
8b5f0ba3a7 daily update 2014-02-21 09:30:38 +10:30
Chung-Lin Tang
d9972968c1 2014-02-20 Chung-Lin Tang <cltang@codesourcery.com>
* elf32-nios2.c (nios2_elf32_relocate_section): Fix calculation
        of GOTOFF relocations.
2014-02-19 21:40:21 -08:00
Alan Modra
b5ad007edc daily update 2014-02-20 09:30:38 +10:30
H.J. Lu
0ff2b86e7c Create the second PLT for BND relocations
Intel MPX introduces 4 bound registers, which will be used for parameter
passing in x86-64.  Bound registers are cleared by branch instructions.
Branch instructions with BND prefix will keep bound register contents.
This leads to 2 requirements to 64-bit MPX run-time:

1. Dynamic linker (ld.so) should save and restore bound registers during
symbol lookup.
2. Change the current 16-byte PLT0:

  ff 35 08 00 00 00	pushq  GOT+8(%rip)
  ff 25 00 10 00	jmpq  *GOT+16(%rip)
  0f 1f 40 00		nopl   0x0(%rax)

and 16-byte PLT1:

  ff 25 00 00 00 00    	jmpq   *name@GOTPCREL(%rip)
  68 00 00 00 00       	pushq  $index
  e9 00 00 00 00       	jmpq   PLT0

which clear bound registers, to preserve bound registers.

We use 2 new relocations:

to mark branch instructions with BND prefix.

When linker sees any R_X86_64_PC32_BND or R_X86_64_PLT32_BND relocations,
it switches to a different PLT0:

  ff 35 08 00 00 00	pushq  GOT+8(%rip)
  f2 ff 25 00 10 00	bnd jmpq *GOT+16(%rip)
  0f 1f 00		nopl   (%rax)

to preserve bound registers for symbol lookup and it also creates an
external PLT section, .pl.bnd.  Linker will create a BND PLT1 entry
in .plt:

  68 00 00 00 00       	pushq  $index
  f2 e9 00 00 00 00     bnd jmpq PLT0
  0f 1f 44 00 00        nopl 0(%rax,%rax,1)

and a 8-byte BND PLT entry in .plt.bnd:

  f2 ff 25 00 00 00 00  bnd jmpq *name@GOTPCREL(%rip)
  90			nop

Otherwise, linker will create a legacy PLT1 entry in .plt:

  68 00 00 00 00       	pushq  $index
  e9 00 00 00 00        jmpq PLT0
  66 0f 1f 44 00 00     nopw 0(%rax,%rax,1)

and a 8-byte legacy PLT in .plt.bnd:

  ff 25 00 00 00 00     jmpq  *name@GOTPCREL(%rip)
  66 90                 xchg  %ax,%ax

The initial value of the GOT entry for "name" will be set to the the
"pushq" instruction in the corresponding entry in .plt.  Linker will
resolve reference of symbol "name" to the entry in the second PLT,
.plt.bnd.

Prelink stores the offset of pushq of PLT1 (plt_base + 0x10) in GOT[1]
and GOT[1] is stored in GOT[3].  We can undo prelink in GOT by computing
the corresponding the pushq offset with

GOT[1] + (GOT offset - &GOT[3]) * 2

Since for each entry in .plt except for PLT0 we create a 8-byte entry in
.plt.bnd, there is extra 8-byte per PLT symbol.

We also investigated the 16-byte entry for .plt.bnd.  We compared the
8-byte entry vs the the 16-byte entry for .plt.bnd on Sandy Bridge.
There are no performance differences in SPEC CPU 2000/2006 as well as
micro benchmarks.

Pros:
	No change to undo prelink in dynamic linker.
	Only 8-byte memory overhead for each PLT symbol.
Cons:
	Extra .plt.bnd section is needed.
	Extra 8 byte for legacy branches to PLT.
	GDB is unware of the new layout of .plt and .plt.bnd.

bfd/

	* elf64-x86-64.c (elf_x86_64_bnd_plt0_entry): New.
	(elf_x86_64_legacy_plt_entry): Likewise.
	(elf_x86_64_bnd_plt_entry): Likewise.
	(elf_x86_64_legacy_plt2_entry): Likewise.
	(elf_x86_64_bnd_plt2_entry): Likewise.
	(elf_x86_64_bnd_arch_bed): Likewise.
	(elf_x86_64_link_hash_entry): Add has_bnd_reloc and plt_bnd.
	(elf_x86_64_link_hash_table): Add plt_bnd.
	(elf_x86_64_link_hash_newfunc): Initialize has_bnd_reloc and
	plt_bnd.
	(elf_x86_64_copy_indirect_symbol): Also copy has_bnd_reloc.
	(elf_x86_64_check_relocs): Create the second PLT for Intel MPX
	in 64-bit mode.
	(elf_x86_64_allocate_dynrelocs): Handle the second PLT for IFUNC
	symbols.  Resolve call to the second PLT if it is created.
	(elf_x86_64_size_dynamic_sections): Keep the second PLT section.
	(elf_x86_64_relocate_section): Resolve PLT references to the
	second PLT if it is created.
	(elf_x86_64_finish_dynamic_symbol): Use BND PLT0 and fill the
	second PLT entry for BND relocation.
	(elf_x86_64_finish_dynamic_sections): Use MPX backend data if
	the second PLT is created.
	(elf_x86_64_get_synthetic_symtab): New.
	(bfd_elf64_get_synthetic_symtab): Likewise.  Undefine for NaCl.

ld/

	* emulparams/elf_x86_64.sh (TINY_READONLY_SECTION): New.

ld/testsuite/

	* ld-x86-64/mpx.exp: Run bnd-ifunc-1 and bnd-plt-1.
	* ld-x86-64/bnd-ifunc-1.d: New file.
	* ld-x86-64/bnd-ifunc-1.s: Likewise.
	* ld-x86-64/bnd-plt-1.d: Likewise.
2014-02-19 11:48:23 -08:00