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

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

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;


>
>> 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