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Max Filippov 148d638429 gas: xtensa: implement trampoline coalescing
There is a recurring pattern in assembly files generated by a compiler
where a lot of jumps in a function are going to the same place. When
these jumps are relaxed with trampolines the assembler generates a
separate jump thread from each source.
Create an index of trampoline jump targets for each segment and see if a
jump being relaxed goes to a location from that index, in which case
replace its target with a location of existing trampoline jump that
results in the shortest path to the original target.

gas/
2017-11-27  Max Filippov  <jcmvbkbc@gmail.com>

	* config/tc-xtensa.c (trampoline_chain_entry, trampoline_chain)
	(trampoline_chain_index): New structures.
	(trampoline_index): Add chain_index field.
	(xg_order_trampoline_chain_entry, xg_sort_trampoline_chain)
	(xg_find_chain_entry, xg_get_best_chain_entry)
	(xg_order_trampoline_chain, xg_get_trampoline_chain)
	(xg_find_best_eq_target, xg_add_location_to_chain)
	(xg_create_trampoline_chain, xg_get_single_symbol_slot): New
	functions.
	(xg_relax_fixups): Call xg_find_best_eq_target to adjust jump
	target to point to an existing jump. Call
	xg_create_trampoline_chain to create new jump target. Call
	xg_add_location_to_chain to add newly created trampoline jump
	to the corresponding chain.
	(add_jump_to_trampoline): Extract loop searching for a single
	slot with a symbol into a separate function, replace that code
	with a call to that function.
	(relax_frag_immed): Call xg_find_best_eq_target to adjust jump
	target to point to an existing jump.
	* testsuite/gas/xtensa/all.exp: Add trampoline-2 test.
	* testsuite/gas/xtensa/trampoline.d: Adjust absolute addresses
	as many duplicate trampoline chains are now coalesced.
	* testsuite/gas/xtensa/trampoline.s: Add _nop so that objdump
	stays in sync with instruction stream.
	* testsuite/gas/xtensa/trampoline-2.l: New test result file.
	* testsuite/gas/xtensa/trampoline-2.s: New test source file.
2017-11-27 15:15:46 -08:00
bfd [PR ld/22263] aarch64: Avoid dynamic TLS relocs in PIE 2017-11-27 11:53:04 +00:00
binutils Fix a seg-fault when displaying notes from a prorgam segment. Check for a NULL string section before attempting compute the name of a separate debug info file. 2017-11-27 11:05:39 +00:00
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gas gas: xtensa: implement trampoline coalescing 2017-11-27 15:15:46 -08:00
gdb fix two issues in gdb.ada/mi_catch_ex.exp (re: "exception-message") 2017-11-27 11:39:45 -08:00
gold Fix typo in ChangeLog entry. 2017-11-19 18:02:31 -08:00
gprof
include Re-apply "elf: Properly compute offsets of note descriptor and next note" 2017-11-24 14:52:15 -08:00
intl Require ngettext in test of system gettext implementation 2017-11-07 15:56:44 +10:30
ld Update PR ld/21562 tests for underscore targets 2017-11-24 08:58:56 -08:00
libdecnumber
libiberty
opcodes Update the simplified Chinese translation of the messages in the opcodes library. 2017-11-27 11:14:38 +00:00
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