xtensa: allow runtime ABI selection

xtensa: allow runtime ABI selection

2020-06-15  Max Filippov  <jcmvbkbc@gmail.com>
bfd/
	* elf32-xtensa.c (XSHAL_ABI, XTHAL_ABI_UNDEFINED)
	(XTHAL_ABI_WINDOWED, XTHAL_ABI_CALL0): New macros.
	(elf32xtensa_abi): New global variable.
	(xtensa_abi_choice): New function.
	(elf_xtensa_create_plt_entry): Use xtensa_abi_choice instead of
	XSHAL_ABI to select PLT code.

gas/
	* config/tc-xtensa.c (XTHAL_ABI_WINDOWED, XTHAL_ABI_CALL0): New
	macros.
	(elf32xtensa_abi): New declaration.
	(option_abi_windowed, option_abi_call0): New enum constants.
	(md_longopts): Add entries for --abi-windowed and --abi-call0.
	(md_parse_option): Add handlers for --abi-windowed and
	--abi-call0.
	(xtensa_add_config_info): Use xtensa_abi_choice instead of
	XSHAL_ABI to format ABI tag.
	* doc/as.texi (Target Xtensa options): Add --abi-windowed and
	--abi-call0 to the list of options.
	* doc/c-xtensa.texi: Add description for options --abi-windowed
	and --abi-call0.
	* testsuite/gas/xtensa/abi-call0.d: New test definition.
	* testsuite/gas/xtensa/abi-windowed.d: New test definition.
	* testsuite/gas/xtensa/abi.s: New test source.

include/
	* elf/xtensa.h (xtensa_abi_choice): New declaration.

ld/
	* emultempl/xtensaelf.em (XSHAL_ABI): Remove macro definition.
	(XTHAL_ABI_UNDEFINED, XTHAL_ABI_WINDOWED, XTHAL_ABI_CALL0): New
	macros.
	(elf32xtensa_abi): New declaration.
	(xt_config_info_unpack_and_check): Set elf32xtensa_abi if it is
	undefined.  Use xtensa_abi_choice instead of XSHAL_ABI to test
	ABI tag consistency.
	(xtensa_add_config_info): Use xtensa_abi_choice instead of
	XSHAL_ABI to format ABI tag.
	(PARSE_AND_LIST_PROLOGUE): Define OPTION_ABI_WINDOWED,
	OPTION_ABI_CALL0 and declare elf32xtensa_abi.
	(PARSE_AND_LIST_LONGOPTS): Add entries for --abi-windowed and
	--abi-call0.
	(PARSE_AND_LIST_OPTIONS): Add help text for --abi-windowed and
	--abi-call0.
	(PARSE_AND_LIST_ARGS_CASES): Add handlers for --abi-windowed and
	--abi-call0.
	* ld.texi: Add description for options --abi-windowed and
	--abi-call0.