Re: [PATCH 5/8] gas: xtensa: rewrite xg_relax_trampoline

["augustine dot sterling at gmail dot com" <augustine dot sterling at gmail dot com>]

On Mon, Nov 27, 2017 at 11:39 AM, Max Filippov <jcmvbkbc@gmail.com> wrote:
> Replace linked list of trampoline frags with an ordered array, so that
> instead of indexing fixups trampolines could be indexed. Keep each array
> in the trampoline_seg structure, so there's no need to rebuild it for
> every new processed segment. Don't run relaxation for each trampoline
> frag, instead run it for each fixup in the current segment that needs
> relaxation at the beginning of each relaxation pass. This way the
> complexity of this process drops from about O(n^2 * m) to about
> O(log n * m), where n is the number of trampoline frags and m is the
> number of fixups that need relaxation in the segment.
>
> gas/
> 2017-11-20  Max Filippov  <jcmvbkbc@gmail.com>
>
>         * config/tc-xtensa.c (trampoline_index): New structure.
>         (trampoline_seg): Replace trampoline list with trampoline index.
>         (xg_find_trampoline, xg_add_trampoline_to_index)
>         (xg_remove_trampoline_from_index, xg_add_trampoline_to_seg)
>         (xg_is_trampoline_frag_full, xg_get_fulcrum)
>         (xg_find_best_trampoline, xg_relax_fixup, xg_relax_fixups)
>         (xg_is_relaxable_fixup): New functions.
>         (J_MARGIN): New macro.
>         (xtensa_create_trampoline_frag): Use xg_add_trampoline_to_seg
>         instead of open-coded addition to the linked list.
>         (dump_trampolines): Iterate through the trampoline_seg::index.
>         (cached_fixupS, cached_fixup, fixup_cacheS, fixup_cache)
>         (fixup_order, xtensa_make_cached_fixup)
>         (xtensa_realloc_fixup_cache, xtensa_cache_relaxable_fixups)
>         (xtensa_find_first_cached_fixup, xtensa_delete_cached_fixup)
>         (xtensa_add_cached_fixup, check_and_update_trampolines): Remove
>         definitions.
>         (xg_relax_trampoline): Extract logic into separate functions,
>         replace body with a call to xg_relax_fixups.
>         (search_trampolines): Replace search in linked list with search
>         in index. Change data type of address-tracking variables from
>         int to offsetT. Replace abs with labs.
>         (xg_append_jump): Finish the trampoline frag if it's full.
>         (add_jump_to_trampoline): Remove trampoline frag from the index
>         if the frag is full.
>         * config/tc-xtensa.h (xtensa_frag_type): Remove next_trampoline.
>         * testsuite/gas/xtensa/trampoline.d: Adjust absolute addresses
>         as the placement of trampolines has slightly changed.
>         * testsuite/gas/xtensa/trampoline.s: Add _nop so that objdump
>         stays in sync with instruction stream.

This is OK.