[Morello] GOT Relocations

[Morello] GOT Relocations

- Implement R_MORELLO_LD128_GOT_LO12_NC and emit the correct
  relocation based on the target register size.
- Add R_MORELLO_GLOB_DAT and R_MORELLO_RELATIVE dynamic relocations for GOT
  entries
- Add support for capabilities in GOT

GOT slots for capabilities need to be 16 byte to accommodate
capabilities.  For this purpose, we delay initialising size and
alignment of the GOT sections until we have walked all relocs in
check_relocs.  If we encounter capability relocations during the walk,
set the GOT entry size and alignment to account for capabilities or
leave it pointer sized otherwise.

bfd/ChangeLog:

2020-10-20  Siddhesh Poyarekar  <siddesh.poyarekar@arm.com>

	* elfnn-aarch64.c (GOT_ENTRY_SIZE): Adjust for C64
	relocations.  Adjust callers.
	(GOT_RESERVED_HEADER_SLOTS, GOT_CAP): New macros.
	(elfNN_aarch64_howto_table): Add R_MORELLO_LD128_GOT_LO12_NC
	and R_MORELLO_GLOB_DAT.
	(elf_aarch64_link_hash_table): New member c64_rel.
	(bfd_elfNN_aarch64_set_options): Initialise it.
	(cap_meta, c64_get_capsize): New functions.
	(aarch64_reloc_got_type): Use GOT_CAP.
	(elfNN_aarch64_final_link_relocate): Add
	R_MORELLO_LD128_GOT_LO12_NC and R_MORELLO_GLOB_DAT.
	(aarch64_elf_create_got_section): Move section initialisation
	into a...
	(aarch64_elf_init_got_section): ... New function.
	(elfNN_aarch64_size_dynamic_sections): Call it.
	(elfNN_aarch64_check_relocs): Add R_MORELLO_LD128_GOT_LO12_NC
	and R_MORELLO_GLOB_DAT.
	(elfNN_aarch64_finish_dynamic_symbol): Emit C64 relocations
	when appropriate.
	(elfNN_aarch64_got_elt_size): New function.
	(elfNN_aarch64_got_header_size): Return GOT entry size based
	on c64_rel.
	(elf_backend_got_elt_size): New macro.
	* elfxx-aarch64.c (_bfd_aarch64_elf_put_addend,
	_bfd_aarch64_elf_resolve_relocation): Add
	BFD_RELOC_MORELLO_LD128_GOT_LO12_NC.
	* libbfd.h (bfd_reloc_code_real_names): Add
	BFD_RELOC_MORELLO_GLOB_DAT and
	BFD_RELOC_MORELLO_LD128_GOT_LO12_NC.
	* reloc.c: Likewise.
	* bfd-in2.h: Regenerate.

gas/ChangeLog:

2020-10-20  Siddhesh Poyarekar  <siddesh.poyarekar@arm.com>

	* config/tc-aarch64.c (parse_operands): Emit C64 relocations
	for got_lo12.  Move old relocation checks from...
	(md_apply_fix): ... here.
	* testsuite/gas/aarch64/morello-ldst-reloc.d: Add tests.
	* testsuite/gas/aarch64/morello-ldst-reloc.s: Likewise.

include/ChangeLog:

2020-10-20  Siddhesh Poyarekar  <siddesh.poyarekar@arm.com>

	* elf/aarch64.h: New relocations R_MORELLO_LD128_GOT_LO12_NC
	and R_MORELLO_GLOB_DAT.

ld/ChangeLog:

2020-10-20  Siddhesh Poyarekar  <siddesh.poyarekar@arm.com>

	* testsuite/ld-aarch64/emit-relocs-morello-1.d: New file.
	* testsuite/ld-aarch64/emit-relocs-morello-1.s: New test file.
	* testsuite/ld-aarch64/aarch64-elf.exp: Add it to test runner.