Re: [Qemu-devel] [PATCH 0/6] *** TCG global variables clean-up ***

[Evgeny Voevodin <e.voevodin@samsung.com>]

On 10/22/2012 07:40 AM, Evgeny Voevodin wrote:
> On 10/19/2012 09:55 PM, Blue Swirl wrote:
>> On Fri, Oct 19, 2012 at 12:42 PM, Evgeny <e.voevodin@samsung.com> wrote:
>>> This set of patches moves global variables to tcg_ctx:
>>> gen_opc_ptr
>>> gen_opparam_ptr
>>> gen_opc_buf
>>> gen_opparam_buf
>>>
>>> Where it was possible I used s->...
>>> Where we don't have an interface to pass a pointer to tcg_ctx, I used
>>> tcg_ctx.xxx
>>> since it is a global variable too.
>> Maybe a pointer should be added so that the references become
>> tcg_ctx_ptr->xxx. This would incur unnecessary pointer dereference
>> penalties though.
>
> I thought about usage of TCGContext * tcg_cur_ctx, but I decided that we
> don't need this until
> we want to use multiple TCG contexts.
> If we would like to introduce such a pointer, then I'd prefer to hold it
> in CPUArchState inside
> CPU_COMMON and initialize it in qemu_tcg_cpu_thread_fn for each CPU:
> env->tcg_cur_ctx = &tcg_ctx;

Oh, I just found out that we don't have an access to CPUArchState form 
tcg-op.h, so we can't get rid of usage of global variable here until we
change interfaces to all functions...

>
>
>>
>>> Build tested for all targets.
>>> Execution tested on ARM.
>>>
>>> I didn't notice any slow-down of kernel boot after this set was applied.
>>>
>>> Evgeny (6):
>>>    tcg/tcg.h: Duplicate global TCG variables in TCGContext
>>>    TCG: Use gen_opc_ptr from context instead of global variable.
>>>    TCG: Use gen_opparam_ptr from context instead of global variable.
>>>    TCG: Use gen_opc_buf from context instead of global variable.
>>>    TCG: Use gen_opparam_buf from context instead of global variable.
>>>    TCG: Remove unused global variables
>>>
>>>   gen-icount.h                  |    2 +-
>>>   target-alpha/translate.c      |   10 +-
>>>   target-arm/translate.c        |   12 +-
>>>   target-cris/translate.c       |   12 +-
>>>   target-i386/translate.c       |   12 +-
>>>   target-lm32/translate.c       |   12 +-
>>>   target-m68k/translate.c       |   10 +-
>>>   target-microblaze/translate.c |   12 +-
>>>   target-mips/translate.c       |   10 +-
>>>   target-openrisc/translate.c   |   12 +-
>>>   target-ppc/translate.c        |   10 +-
>>>   target-s390x/translate.c      |   10 +-
>>>   target-sh4/translate.c        |   10 +-
>>>   target-sparc/translate.c      |   10 +-
>>>   target-unicore32/translate.c  |   12 +-
>>>   target-xtensa/translate.c     |    8 +-
>>>   tcg/optimize.c                |   62 ++++----
>>>   tcg/tcg-op.h                  |  324
>>> ++++++++++++++++++++---------------------
>>>   tcg/tcg.c                     |   84 +++++------
>>>   tcg/tcg.h                     |   10 +-
>>>   translate-all.c               |    3 -
>>>   21 files changed, 321 insertions(+), 326 deletions(-)
>>>
>>> --
>>> 1.7.9.5
>>>
>
>


-- 
Kind regards,
Evgeny Voevodin,
Technical Leader,
Mobile Group,
Samsung Moscow Research Center,
e-mail: e.voevodin@samsung.com