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.

1 files changed, 11 insertions, 0 deletions

diff --git a/ld/ld.texi b/ld/ld.texi
index b89c1a5..ecdbf77 100644
--- a/ld/ld.texi
+++ b/ld/ld.texi
@@ -8565,6 +8565,17 @@ more than performance.  With this option, the linker will not insert
 no-ops or widen density instructions to preserve branch target
 alignment.  There may still be some cases where no-ops are required to
 preserve the correctness of the code.
+
+@item --abi-windowed
+@itemx --abi-call0
+Choose ABI for the output object and for the generated PLT code.
+PLT code inserted by the linker must match ABI of the output object
+because windowed and call0 ABI use incompatible function call
+conventions.
+Default ABI is chosen by the ABI tag in the @code{.xtensa.info} section
+of the first input object.
+A warning is issued if ABI tags of input objects do not match each other
+or the chosen output object ABI.
 @end table
 
 @ifclear GENERIC