[Qemu-arm] [PATCH v4 00/11] TCG optimizations for 2.10

[Emilio G. Cota]

v3 for context: 
https://lists.gnu.org/archive/html/qemu-devel/2017-04/msg04795.html

Changes from v3:

- Added reviewed-by tags.

- Added a couple of suggested-by tags that I forgot to add in v3
  regarding lookup_and_goto_ptr and i386's implementation of goto_ptr.

- lookup_tb_ptr
  + Dropped the unnecessary exit_request check, as suggested by Paolo and
    Richard.
  + Only get the CPU state if we get a tb from the jmp_cache, as suggested
    by Richard.
  + Added tb_htable_lookup if we miss in tb_jmp_cache, as suggested by
    Richard. This requires an extra patch to export tb_htable_lookup.

- goto_ptr: add IMPL(has_goto_ptr), as pointed out by Richard.

- target/arm: added a comment about gen_jr. See the v3 thread for why
  it is needed.

- target/i386: use TCGV_UNUSED instead of (ab)using NULL on a TCGv,
  as suggested by Richard. Also took his suggestion to simplify
  the addition of jr + cs_base.
  To minimize churn I renamed gen_eob_worker to do_gen_eob_worker,
  which takes the newly added argument.

I have *not* re-run all experiments, because it takes several hours and
performance hasn't changed much from v3, as can be seen in these two charts:
* spec06int user-mode, test input, v2.9.0 baseline: http://imgur.com/ME2eMq1
* spec06int softmmu, test input, v3 baseline: http://imgur.com/Clolu9Z
The perf differences are mostly due to adding the htable check. Note that
its impact is small, since tb_jmp_cache has a %hit rate in the high 90's.

You can inspect/fetch the changes at:
  https://github.com/cota/qemu/tree/tcg-opt-v4

Thanks,

                Emilio