[PowerPC64] pc-relative TLS relocations

[PowerPC64] pc-relative TLS relocations

This patch supports using pcrel instructions in TLS code sequences.  A
number of new relocations are needed, gas operand modifiers to
generate those relocations, and new TLS optimisation.  For
optimisation it turns out that the new pcrel GD and LD sequences can
be distinguished from the non-pcrel GD and LD sequences by there being
different relocations on the new sequence.  The final "add ra,rb,13"
on IE sequences similarly needs a new relocation, or as I chose, a
modification of R_PPC64_TLS.  On pcrel IE code, the R_PPC64_TLS points
one byte into the "add" instruction rather than being on the
instruction boundary.

GD:
 pla 3,z@got@tlsgd@pcrel	  # R_PPC64_GOT_TLSGD34
 bl __tls_get_addr@notoc(z@tlsgd) # R_PPC64_TLSGD and R_PPC64_REL24_NOTOC
  edited to IE
   pld 3,z@got@tprel@pcrel
   add 3,3,13
  edited to LE
   paddi 3,13,z@tprel
   nop

LD:
 pla 3,z@got@tlsld@pcrel	  # R_PPC64_GOT_TLSLD34
 bl __tls_get_addr@notoc(z@tlsld) # R_PPC64_TLSLD and R_PPC64_REL24_NOTOC
 ..
 paddi 9,3,z2@dtprel
 pld 10,z3@got@dtprel@pcrel
 add 10,10,3
  edited to LE
   paddi 3,13,0x1000
   nop

IE:
 pld 9,z@got@tprel@pcrel	  # R_PPC64_GOT_TPREL34
 add 3,9,z@tls@pcrel		  # R_PPC64_TLS at insn+1
 ldx 4,9,z@tls@pcrel
 lwax 5,9,z@tls@pcrel
 stdx 5,9,z@tls@pcrel
  edited to LE
  paddi 9,13,z@tprel
  nop
  ld 4,0(9)
  lwa 5,0(9)
  std 5,0(9)

LE:
 paddi 10,13,z@tprel

include/
	* elf/ppc64.h (R_PPC64_TPREL34, R_PPC64_DTPREL34),
	(R_PPC64_GOT_TLSGD34, R_PPC64_GOT_TLSLD34),
	(R_PPC64_GOT_TPREL34, R_PPC64_GOT_DTPREL34): Define.
	(IS_PPC64_TLS_RELOC): Include new tls relocs.
bfd/
	* reloc.c (BFD_RELOC_PPC64_TPREL34, BFD_RELOC_PPC64_DTPREL34),
	(BFD_RELOC_PPC64_GOT_TLSGD34, BFD_RELOC_PPC64_GOT_TLSLD34),
	(BFD_RELOC_PPC64_GOT_TPREL34, BFD_RELOC_PPC64_GOT_DTPREL34),
	(BFD_RELOC_PPC64_TLS_PCREL): New pcrel tls relocs.
	* elf64-ppc.c (ppc64_elf_howto_raw): Add howtos for pcrel tls relocs.
	(ppc64_elf_reloc_type_lookup): Translate pcrel tls relocs.
	(must_be_dyn_reloc, dec_dynrel_count): Add R_PPC64_TPREL64.
	(ppc64_elf_check_relocs): Support pcrel tls relocs.
	(ppc64_elf_tls_optimize, ppc64_elf_relocate_section): Likewise.
	* bfd-in2.h: Regenerate.
	* libbfd.h: Regenerate.
gas/
	* config/tc-ppc.c (ppc_elf_suffix): Map "tls@pcrel", "got@tlsgd@pcrel",
	"got@tlsld@pcrel", "got@tprel@pcrel", and "got@dtprel@pcrel".
	(fixup_size, md_assemble): Handle pcrel tls relocs.
	(ppc_force_relocation, ppc_fix_adjustable): Likewise.
	(md_apply_fix, tc_gen_reloc): Likewise.
ld/
	* testsuite/ld-powerpc/tlsgd.d,
	* testsuite/ld-powerpc/tlsgd.s,
	* testsuite/ld-powerpc/tlsie.d,
	* testsuite/ld-powerpc/tlsie.s,
	* testsuite/ld-powerpc/tlsld.d,
	* testsuite/ld-powerpc/tlsld.s: New tests.
	* testsuite/ld-powerpc/powerpc.exp: Run them.